Design, synthesis, spectroscopic characterizations, in vitro pancreatic lipase as well as tyrosinase inhibition evaluations and in silico analysis of novel aryl sulfonate-naphthalene hybrids

Abstract One of the primary purposes of this study is to synthesize new aryl sulfonate-naphthalene hybrid structures possessing divergent electron-withdrawing and electron-releasing functional groups. Following the improved reaction conditions, we successfully gathered ten distinct sulfonate derivatives (3a-j) with good yields. The synthesized naphthalene-based sulfonate derivatives were then characterized using appropriate analytical methods (FT-IR, 1H-NMR, 13C-NMR, HRMS, and elemental analysis). Additionally, in vitro and in silico enzyme inhibitory properties of the prepared aryl sulfonate-naphthalene hybrid structures were evaluated against pancreatic lipase and tyrosinase enzymes. Corresponding in vitro enzyme activity investigations revealed that the produced compounds inhibit pancreatic lipase and tyrosinase enzymes significantly. According to the lowest IC50 values, 3h (95.3 ± 4.0 µM) demonstrated the most effective inhibition against pancreatic lipase, whereas 3a (40.8 ± 3.3 µM) was found as the most effective inhibition against the tyrosinase. According to in silico studies, 3a exhibited the highest affinity value (−9.9 kcal/mol) against pancreatic lipase, whereas 3f demonstrated the best affinity value (−8.7 kcal/mol) against tyrosinase. Furthermore, we investigated various structural and physicochemical properties of the target molecules, namely frontier orbital’ (HOMO, LUMO, and bandgap) energies (including their corresponding contour plots), global reactivity descriptors (ionization energy and electron affinity), and electronegativity values gathered from ground-state (GS) density functional theory (DFT) calculations. These investigations demonstrated that the observed electrostatic interactions effectively contributed to the studied molecules’ experimentally demonstrated enzyme inhibition potential. Also, ADMET studies were evaluated to enlighten the molecular interactions of the compounds with the enzymes. Communicated by Ramaswamy H. Sarma


Introduction
In the relevant scientific discipline, there is a rising interest in enzyme inhibition screening and detection investigations for identifying new reliable medications. In this study, we sought to decipher the possible enzyme inhibitor characteristics of newly produced compounds against tyrosinase and pancreatic lipase enzymes. Designing the synthetic compounds for enzyme inhibitors is a hot topic research area and has been the subject of many published papers (Akocak et al., 2021;Behl et al., 2021;Çakmak et al., 2022;G€ um€ uş et al., 2022). Although many synthetic compounds have been screened for their inhibitory enzyme activities, the number of approved drugs for enzyme inhibitors remains limited and does not meet the needs of the drug industry (Cetin et al., 2021;Demir et al., 2020;Turkan et al., 2019).
Tyrosinase (mono/polyphenol oxidase) is a critical enzyme family in the melanin biosynthesis pathway responsible for skin and hair pigmentation . Melanin has functions for skin protection against harmful ultraviolet radiation and prevention of cancer development. However, overexpression of melanin leads to several skin diseases (Kim et al., 2016). Thus, tyrosinase inhibition is crucial in preventing the harmful results of excessive melanin production. Tyrosinase inhibitors have been utilized as skin lightening agents in cosmetics. Many tyrosinase inhibitors derived from natural and synthetic sources have recently been found. Among the several substances examined, kojic acid, ascorbic acid, arbutin, and hydroquinone were acknowledged as standard tyrosinase enzyme inhibitors (Pillaiyar et al., 2017).
Pancreatic lipase is a digestive enzyme that aids in the breakdown of dietary lipids in the gastrointestinal tract. Obesity is thought to be caused chiefly by excess fat accumulated in the body (Kumar & Chauhan, 2021). Obesity is associated with several health issues or metabolic diseases, including hypertension, diabetes mellitus, cardiovascular issues, and some forms of cancer (Li et al., 2021). Pancreatic lipase inhibitors have been used to treat obesity because they reduce fat absorption via the small intestine . Among the many screened inhibitor compounds, orlistat has been confirmed and used as an effective obesity drug with a potent pancreatic lipase inhibitor (George et al., 2021).
Naphthalene derivatives have been extensively studied with various applications (Ciupak et al., 2021;Erdo gan et al., 2021;Wang et al., 2020). Some potent inhibitors (I-VI) of the naphthalene derivatives shown in Scheme 1 were investigated previously. It has been reported that the anticancer activities of synthesized 1,5-N,N'-substituted-2-(substituted naphthalenesulfonyl) glutamamide derivatives (I, II) were evaluated against Ehrlich Ascites Carcinoma (EAC) cells in Swiss Albino mice as anticancer agents (Halder et al., 2010). The emphasis of interest has shifted to investigations on synthesizing modified naphthalene-based derivatives (III) with pharmacological characteristics, such as acetylcholinesterase and paraoxonase 1 inhibition (Shirinzadeh et al., 2022). Carbonic anhydrase inhibition properties of imino-methylnaphthalen-2-ol (IV) were investigated in a recent study (Abbas et al., 2018). Furthermore, hybrid compounds containing naphthalene moiety (V) as potent antioxidants and lipoxygenase inhibitors were synthesized, and molecular modeling studies were accordingly reported (Ali et al., 2020). It was encountered that naphthalene analogs (VI) displayed their antimitotic effects in human cancer cells by disrupting the microtubule network, followed by G2/M arrest of the cell cycle (Maya et al., 2005). Another study reported that acetone O-(4 chlorophenylsulfonyl) oxime, a sulfonated derivative, has a significant potential for phytoremediation studies (Yetişsin & Kardeş, 2022).
In this study, we synthesized ten novel naphthalene-based sulfonated derivatives by a triethylamine (TEA)-mediated mild reaction process. Then, the synthesized compounds were screened for their in vitro as well as in silico pancreatic lipase and tyrosinase inhibitory activities. Moreover, the density functional theory (DFT) and ADMET (absorption, distribution, metabolism, excretion, and toxicity) predictions of the naphthalene-based sulfonate derivatives were also performed to elucidate their physicochemical properties and reactivity patterns in order to describe their potent applicabilities.
The melting points were measured by a thermo-scientific capillary. 1 H (400MHz) and 13 C (100 MHz) NMR spectra were gathered using a Bruker DRX-400. High-resolution mass spectra (HRMS) data were collected using Agilent Q-TOF Mass Spectrometer (Acquisition SW Version (6200 series TOF/6500 series Q-TOF B.08.00 (B8058.0)) in ESI mode. Elemental analysis studies were conducted with LECO CHNS-932 Elementary Chemical Analyzer. Thermo multi-scan microplate spectrophotometer was used for enzyme kinetic measurements.

In vitro tyrosinase inhibition assay
Tyrosinase inhibition properties of the screened naphthalene compounds were determined according to a previous study (Korkmaz & Bursal, 2022b). Briefly, different concentrations (20-160 mM) of the screened compounds in 130 mL phosphate buffer (0.05 M, pH 6.8) and 50 mL tyrosine substrate solutions were pipetted to a 96-well microplate. The reaction was started by adding 25 mL (25 EU) mushroom tyrosinase enzyme solution. After the incubation of 5 min period at 25 C, the microplate was run in the spectrophotometer at 490 nm and the absorbance changes for 5 min were recorded. Also, the control sample (the same procedure only without adding the tested compounds was used to compare the results of the samples. The following equation was used to calculate the inhibitions of compounds against tyrosinase and pancreatic lipase activities. In this equation A is the absorbance of the control sample and B is the absorbance of the screened samples. The compounds' IC 50 values (concentration of a compound able to inhibit 50% of the enzyme activity) were calculated from the obtained equations of the activity-concentration graph.

In vitro pancreatic lipase inhibition assay
Enzyme inhibition properties of the screened 3a-j compounds against pancreatic lipase (PL) were determined according to a previous study (Korkmaz & Bursal, 2022c). Firstly, the PL solution was prepared by solving 100 mg porcine pancreatic lipase in a 10 mL buffer solution (0.05 M, pH: 6.8) and centrifuged for 10 min (4000 rpm). The supernatant was separated and stored as PL enzyme stock solution for the enzyme assays. The different concentrations of compounds (20-160 mM) in the buffer solution and 20 mL of enzyme solution were pipetted to a 96-well microplate and incubated for 5 min at 37 C. Then, 20 mL of the substrate (4nitrophenyl butyrate, 10 mM in acetonitrile) was added to each microplate well. The microplate was run in a spectrophotometer (Thermo Scientific Multiskan GO) at 405 nm. Orlistat was used as a positive standard in the procedure.

Quantum chemical calculations
Three-dimensional (3 D) structures of pancreatic lipase and tyrosinase inhibitor candidates were prepared with GaussView 5.0 (Dennington et al., 2009) and the geometry optimization studies were performed by using Gaussian 09 program suite (Frisch et al., 2016) at the DFT/B3LYP/6-311g(d,p)) level of theory. In the concomitant step, the optimized structures were checked to be accurate relative energy minima of the potential energy surfaces through corresponding frequency calculations, and no imaginary frequencies indicate the intrinsic stability of the investigated compounds. The details of these calculations are provided in ESI †.
With the completion of the optimization studies, based on this determined one-step reaction pathway, we could obtain the target sulfonate derivatives 3a-j in good yields.

Structural characterization
The naphthalene-based sulfonate derivatives were purified, and structural characterization of the compounds 3a-j was accomplished using appropriate techniques, including FT-IR, 1 H-NMR, 13 C-NMR, HRMS, and elemental analysis.
The FT-IR spectra for a typical aldehyde carbonyl peak of 3a, 3 b, 3c, 3d, 3e, and 3f were observed at 1686. 95, 1685.73, 1685.67, 1685.30, 1688.48, and 1688.87 cm À1 , respectively, while the rest of compounds 3 g, 3 h, 3i, and 3j did not appear at this region. In addition, the observation of specific strong ArSO 2 OAr band peaks (approximately 1380 and 1180 cm À1 ) in the FT-IR spectra of all compounds 3a-j indicated that the compounds were bound with aryl sulfonyl chlorides.
The naphthalene-based sulfonate derivatives 3a-f exhibited the aldehyde (Ar-CHO) protons as characteristic singlets at 10.42, 10.34, 10.47, 10.70, 10.70, and 10.40 ppm, respectively. Also, the absence of -OH peaks of compounds 3a-j in the 1 H NMR spectrum has indicated the bonding formation of the sulfonate structures.
The formyl peak of 3a among the compounds with the best efficacy was consistent at 10.42 ppm in the 1H NMR spectrum.3a has demonstrated two multiplets centered from 7.70 to 7.64 ppm as one proton and 7.62-7.56 ppm as one proton. In addition, six doublet signals of 3a were observed at 9.16 (d, Ar-H) due to the benzene and naphthyl moiety. Also, the methoxy proton peak of 3a was observed as a single signal at 3.90 ppm. Consequently, the number of protons observed in this compound is consistent with the expected number of protons in the 1 H NMR spectrum. The synthesized sulfonate derivatives bearing different substituents 3a-j are depicted in Table 1.
Similarly, the proton signals of 3i due to the aromatic moiety were monitored at 7.85-7.73 (m, 3H, Ar-H), 7.55-7.43 (m, 3H, Ar-H), 7.13 (d, 1H, J ¼ 8.90 Hz, Ar-H), and 6.99 (s, 2H, Ar-H) in the aromatic region. Three methyl signals (two methyl peaks overlapped) of 3i were observed at two signals at 2.60 and 2.34 ppm as singlets in the aliphatic region. In other compounds, the proton peaks were compatible as expected (see supplemental data).
All 13 C NMR signals of compounds 3a-j were clearly determined (see supplemental data). The expected formyl carbon peaks of six compounds 3a-f were measured at 189.9, 190.0, 189.6, 190.1, 190.7, and 190.2 ppm, respectively. As expected, no formyl peak was observed in other compounds 3 g, 3 h, 3i, and 3j. As expected, 16 carbon peaks in 13 C NMR of the compounds 3a, 3 b, 3c, 3e, 3i, and 3j were observed in the aromatic region 14 carbon signals which are two of these peaks overlapped the two co-peaks. The carbon peaks of compounds 3d, 3f, 3 g, and 3 h were observed as the expected peaks. All of the HRMS masses were predicted as [M þ Na] and [M þ H] values. The HRMS spectra values of compounds 3a-j showed the expected molecular peak of pure compounds. As a result, spectrum analyzes of compounds 3a-j showed that these compounds were obtained in pure form. All of the CHNS elemental analyses were corrected the compounds.

Determination of tyrosinase inhibitory activities
The synthesized naphthalene-bearing sulfonate derivatives were screened to see their effects on tyrosinase enzyme activity. The IC 50 values were calculated to predict their inhibitor potentials. The IC 50 values of the synthesized Scheme 2. TEA-mediated facile synthesis of naphthalene-bearing sulfonate derivatives.
compounds were calculated in the range of 40.8 ± 3.34 lM and 112.6 ± 6.7 lM. The enzyme inhibitory activities of the compounds were compared to kojic acid, a well-known tyrosinase inhibitor. Among the synthesized compounds, 3a, 3c, and 3d were determined to have more effective tyrosinase inhibitions. The IC 50 values of 3a (40.8 ± 3.3), 3c (43.3 ± 3.5), and 3d (43.3 ± 3.6) were determined to be comparable levels to the kojic acid IC 50 value (19.2 ± 0.3 lM) which was noted in a recent study .Also, the inhibitory activities of the compounds were calculated as kojic acid equivalent (KAEq) to compare their results with the standard inhibitor. The KAEq values of the synthesized compounds were calculated in the range of 0.17 and 0.47 KAEq. The results suggest that all investigated compounds' inhibitory activities were lower than the kojic acid. The inhibition effects of the synthesized compounds on tyrosinase enzyme were given as activity/concentration graph in Figure 1. Herein, the decreasing enzyme activity (%) shows the inhibitor power of the compound.
Tyrosinase catalyzes the hydroxylation of L-tyrosine and the oxidation of L-DOPA (3,4-dihydroxyphenylalanine) to odopaquinone. Tyrosinase contains a copper complex in the catalytic center and hydroxyl groups of the substrate are suggested to be bound to the copper atoms causing inhibition of the enzyme. Overall, most of the screened compounds showed moderate inhibition against tyrosinase compared to the standard compound (kojic acid). Generally, the existence of halogen substitutions increased tyrosinase inhibition. In terms of the structure-activity relationship point, the tyrosinase inhibition activity order of the most effective sulfonate derivatives with having different substituents was found to be compounds 3a (methoxybenzene), 3c (bromobenzene), and 3d (dichlorobenzene), respectively.
Various researchers evaluated the tyrosinase inhibitory activities of many synthetic or natural compounds. Inhibition effects of many phenolics, flavonoids, coumarins, chalcones, terpenoid natural compounds and pyridine, carbazone, azole, and thiazolidine derivatives synthetic compounds were collected in a paper as a comprehensive review on tyrosinase inhibitors (Zolghadri et al., 2019).
Structure-activity relationship studies showed that the existence and location of the hydroxyl groups on aromatic rings are the essential factors in the tyrosinase inhibition effects of natural or synthetic compounds. Kojic acid which is as a well-known tyrosinase inhibitor, has two hydroxyl groups in its chemical structure. Although the synthesized sulfonate compounds do not contain hydroxyl groups, their halogen substitutions are considered to affect tyrosinase inhibition. A previous study reported that halogen-substituted sulfonamide derivatives could reduce tyrosinase activity and showed potent tyrosinase inhibitions (Huo et al., 2021).

Determination of pancreatic lipase inhibitory activities
The inhibition IC 50 values of the synthesized compounds on pancreatic lipase were calculated to be between the range of 95.3 ± 4.0 lM and 173.2 ± 4.7 lM. All of the compounds 3a-j were determined to have slightly higher IC 50 values than the orlistat IC 50 value (63.0 ± 4.8 lM). Among the synthesized compounds, 3 h and 3e were determined to have more effective pancreatic lipase inhibitions than the other compounds. The IC 50 values of the 3 h (95.3 ± 4.0 lM) and 3e (99.0 ± 2.7 lM) were determined to be at comparable levels to the orlistat IC 50 value. Also, pancreatic lipase inhibitions of the compounds were determined as orlistat equivalent (OEq) to compare their results with the standard inhibitor. The OEq values of the synthesized compounds were calculated between 0.36 and 0.66 OEq. Remarkably, most of the screened compounds showed around half of the inhibitory effect of orlistat (0.5 OEq) ( Table 2). According to the data of this study, 3 h was detected to be the most effective inhibitor against the pancreatic lipase understood from the lowest IC 50 value (95.3 ± 4.0 lM) and highest orlistat equivalent value (0.66 OEq). The inhibition effects of the synthesized compounds 3a-j on pancreatic lipase were given as an activity/ concentration graph in Figure 2.
Orlistat is approved to be the main drug in the clinical treatment of obesity as a pancreatic lipase inhibitor. Orlistat has both lipophilic and hydrophilic parts in its chemical structure. When we checked the structure-activity relationship of the synthesized compounds with orlistat, the most potent inhibitor substituents have relatively larger lipophilic parts than the others. In terms of the structure-activity relationship point, the pancreatic lipase inhibition activity order of the synthesized sulfonate derivatives with having different substituents was found to be standard compound (orlistat) > 3 h (naphthalen-2-yl 2,5-dichlorobenzenesulfonate) > 3e (1-formylnaphthalen-2-yl 2,4,6-triisopropylbenzenesulfonate) > 3j (naphthalen-2-yl 2,4,6-triisopropylbenzenesulfonate), respectively. According to the results, the existence of halogen and triisopropyl substitutions causes pancreatic lipase inhibition. In recent years, some studies have evaluated the inhibition potentials of various sulfonate compounds against some enzymes. Analyses of naphthalene-bearing sulfonate compounds provide insights into the relationship between the pancreatic lipase inhibitory effects and substituted naphthalene groups. The compound 3 h, which contains naphthalen-2-yl 2,5-dichlorobenzene substitution, was detected to be the most effective inhibitor of pancreatic lipase. Likewise, a former study reported that 2-naphthyl unit moiety was beneficial for pyrazolone derivatives to inhibit the pancreatic lipase enzyme .
Overall, the synthesized naphthalene-bearing sulfonate derivatives showed diverse effects on tyrosinase and pancreatic lipase enzymes. According to the gathered results, 3 h demonstrated the most effective inhibition against pancreatic lipase, whereas 3a was the most effective inhibitor against tyrosinase. Remarkably, they had opposite effects on the enzymes due to the active sites of the enzymes. For instance, 3 h and 3e were detected to be the most effective inhibition against pancreatic lipase, but their tyrosinase inhibitions were at low values compared to the standards.

Quantum chemical calculations
As already stated, we intended to contribute a viable strategy to improve the inhibitor activity of sulfonate derivatives against pancreatic lipase and tyrosinase. Thus, we decided to retain the identical naphthalene subunits on the backbone of the target compounds, whereas we decorated them with divergent subunits. Therefore, a systematic approach to evaluate the physicochemical behaviors of the investigated molecules is to perform first experimentally. Then, the DFT calculations were followed by enzyme activity and molecular docking studies. At first glance, to preliminarily appraise the potent activity of the mentioned naphthalene possessing sulfonate derivatives, we have computationally investigated target compounds by performing geometry optimization and subsequently executed frequency calculations to ensure their local minima. According to the obtained data, we have predicted frontier orbital energies comprising HOMO (Highest Occupied Molecular Orbital, LUMO (Lowest Unoccupied  [a] 19.2 ± 0.3 1.0 Orlistat [b] 63.0 ± 4.8 1.0 The bond highlighted values are the low IC 50 values which show the effective inhibition.
[a] Standard inhibitor of tyrosinase.
[b] Standard inhibitor of pancreatic lipase.  Molecular Orbital), and relatively their bandgap energies. We have also calculated ionization energies and electron affinity values in the following step. These outputs, including the dipole moment values, are depicted in Table 3. According to theoretical outputs, it could be depicted that formyl (-CHO) fragment containing molecules (compounds: 3a to 3f-included-have unquestionably the lowest bandgap values ranging between 4.162 eV (compound no: 3f) and 4.217 eV (compound no: 3e). On the other hand, pristine naphthalene units possessing structures' (compounds 3 g to 3j) bandgap energies were found to be between 4.305-4.686 eV. This phenomenon might be explained by the inclusion of the electron-withdrawing groups and their lowering effect on the LUMO energy levels of the target compounds, consequently dominating and reducing the predicted bandgap energy values. In this concept, LUMO energy levels of compounds 3a to 3f were found between À2.220 and À2.524 eV, whereas a higher energy distribution pattern was seen as À1.593 to À2.116 eV for the compounds 3 g to 3j. As a result, these observations were interpreted in Table 4. Frontier molecular orbital's contour plots, Mulliken charge distribution, dipole moment vector, and ESP maps for the most effective tyrosinase (3a, 3c, and 3d) inhibitors among the investigated compounds' series. Table 5. Frontier molecular orbital's contour plots, Mulliken charge distribution, dipole moment vector, and ESP maps for the most effective pancreatic lipase (3e, 3 h, and 3j) inhibitors among the investigated compounds' series.
light of the lower bandgap values seen in systems containing formyl units. Following the calculation of the frontier orbital energy values, the representative contour plots of HOMO and LUMO orbitals, Mulliken charge distribution, and electrostatic potential (ESP) maps of the most potent inhibitor candidates for tyrosinase (3a, 3c, and 3d) and pancreatic lipase (3e, 3 h, and 3j determined from the enzyme activity studies are also provided in Tables 4 and 5, respectively (also see ESI † for data on the rest of the compounds). Accordingly, HOMO orbitals were predominantly localized on the naphthalene-containing fragment (which acts as a donor unit) for the entire set of investigated compounds. In contrast, LUMO orbitals were mainly localized on the substituent-containing (alkyl, aryl, or haloaryl) subunit part. These two fragments were separated by a sulfonate unit (which could be evaluated as a linker) and resulted in constructing the V-shaped geometrical orientation (corresponding bond angle values varied between 101 and 104 ).
Moreover, the corresponding ESP maps revealed the accumulation of the negative electrostatic potential on the sulfonate unit and dominated the rotation of the dipole moment vector. This uniform charge distribution could contribute to the observed enzyme inhibition potential of the investigated molecules against pancreatic lipase and tyrosinase by producing strong electrostatic interactions, including hydrogen bonding and p-p stacking (Pettersen et al., 2004;Trott & Olson, 2010).

Molecular docking studies
Molecular docking is a required field of study for elucidating protein-ligand interactions. (Alanazi et al., 2022;Aziz et al., 2020Aziz et al., , 2021Elkady et al., 2022). Initially, molecular docking studies were performed for tyrosinase (PDB ID: 2Y9W) with compounds 3a, 3c, 3d, and 3f, which were the most effective in in vitro studies. Also, molecular docking of compounds 3a, 3e, 3 h, and 3j with pancreatic lipase receptor (PDB ID: 1ETH) was also implemented. The best predicted experimental binding pose and crystallized ligand determined were checked against structural alignment to validate the insertion procedure. It was calculated redocking for the co-crystallized form of di(hydroxyethyl)ether) (PEG) and tetraethylene glycol monooctyl ether (TGME). Root Mean Square Deviations (RMSD) values were found at 0.810 Å (TGME) and 1.608 Å (PEG). The RMSD values are acceptable for validation studies (Menteşe et al., 2018;Mirzazadeh et al., 2021;Yuriev et al., 2011). It exhibited superimposes of the predicted and the co-crystal (Figure 3).

Molecular docking analysis of tyrosinase
The most effective naphthalene-based sulfonate derivatives obtained from the in vitro enzyme methods were subjected to molecular docking analyses. For this purpose, compounds 3a, 3c, 3d, and 3f were used to evaluate in silico inhibition activity with tyrosinase (PDB ID: 2Y9W) which was obtained from the Protein Data Bank (PDB) (www.pdb.org). The best affinity of compounds 3a, 3c, 3d, and 3f with tyrosinase exhibited À8.0, À8.5, À8.3, and À8.7 kcal/mol energy values, respectively (Table 7). The most effective affinity value versus tyrosinase was obtained from 3f (À8.7 kcal/mol). The 2 D structures and H-bond interaction pose of the naphthalenebased sulfonate derivatives (3a, 3c, 3d, and 3f) with tyrosinase were exhibited in Figure 4.
Using the molecular docking study methodology, the best affinity values of kojic acid with tyrosinase were observed as À5.1 kcal/mol. The synthesized compounds (3a, 3c, 3d, and 3f) had relative levels with the kojic acid affinity value ( Table  6). The interaction of compound 3a with tyrosinase was determined by a carbon-hydrogen bond (TYR A:310) and conventional hydrogen bond (ASP A:311) as hydrogen bond effects. In addition, it was indicated that Pi-Cation interaction (LYS A:378) and GLU A:355 of the p-anion interaction were noted as an electrostatic effect, as well as PHE A:367 of the p-p T-shaped and LYS A:378 of the p-alkyl interactions were observed as hydrophobic effects. The molecular docking interaction study of compound 3f with tyrosinase was noted to be the same as with compound 3a. The interaction of compound 3d with tyrosinase, unlike compounds 3a and 3c, depicted conventional hydrogen bond (GLN A:306) and carbon-hydrogen bond (ASP A:356, LYS A:375, and THR A:307) as hydrogen bond effects. The interaction of compound 3f with tyrosinase showed the same interactions (electronic and hydrophobic) compared to compounds 3c and 3d except for all hydrogen bonds. The interactions of compounds 3a and 3c with tyrosinase, showed the same interaction as conventional hydrogen bonds (ASP A:311) like standard kojic acid. Similarly, the interaction of compound 3d with tyrosinase exhibited the same interaction as conventional hydrogen bonds (GLN A:306) like kojic acid. The interaction of naphthalene-based sulfonate derivative 3f with tyrosinase demonstrated the different interactions compared to kojic acid. The activity order of the compounds in the in vitro study was 3a > 3c ¼ 3d > 3f. According to the in silico studies, the activity order was 3f > 3c > 3d > 3a for their best affinity values. Therefore, there is no compatibility between in silico and in vitro studies. Hydrogen bonding is the best interaction type of intermolecular interaction. When the compounds were compared in terms of hydrogen bond interaction in the molecular docking study, it was observed that compounds3a, 3c, and 3d interacted with the same amino acids as similar to kojic acid (ASP A: 311 for compounds 3a and 3c, GLN A: 306 for compound 3d). In the hydrogen bond interaction, the strength of the interaction increases as the distance decreases. The hydrogen bond interaction distance of 3a, 3c, and kojic acid with the same amino acid (ASP A:311) were 2.681, 2.720, and 2.560 Å, respectively. Similarly, the hydrogen bond interaction distance of 3d and kojic acid with the same amino acid (GLN A:306) were 2.999 and 2.348 Å, respectively. It is the least hydrogen bond interaction distance compound 3a after the standard kojic acid. According to the hydrogen bond interaction effect, compound 3a showed the best efficacy as it was found in vitro studies.

Molecular docking analysis of pancreatic lipase
The naphthalene-based sulfonate derivatives (3a, 3e, 3 h, and 3j) were used to evaluate inhibition activity with pancreatic lipase (PDB ID:1ETH) obtained from the PDB server. The best affinity of the compounds3a, 3e, 3 h, and 3j with pancreatic lipase exhibited À9.9, À8.6, À9.8, and À9.4 kcal/mol energies, respectively (Table 7). Among the investigated compounds, the best affinity value with pancreatic lipase was obtained with compound 3a (À9.9 kcal/mol). The 2 D structure and hydrogen bond poses of the compounds with tyrosinase were demonstrated in Figure 5.
Using the molecular docking study, the most effective affinity value of orlistat (with pancreatic lipase) was found as À7.1 kcal/mol. The synthesized compounds (3a, 3e, 3 h, and 3j) had a higher affinity value than the orlistat. The activity order of the compounds in the in vitro study was 3 h > 3e > 3j > 3a. Hence, the activity order of the compounds in the in silico studies was 3a > 3h > 3j > 3e according to the best affinity values. While compounds 3e, 3 h, and   The obtained results of compounds 3a-j are listed in Table 8. The HIA values obtained from PreADMET software were found as >70 for the compounds 3a-j (Oja & Maran, 2018). It was determined that all compounds 3a-j exhibited well absorption from the human intestinal absorption (HIA) from 70% to 100%. It was found that the Caco2 values of compounds 3a-j demonstrated middle permeability (Caco2 > 70 is high, Caco2 ¼ 4-70 is middle, and Caco2 < 4 is low) . Also, BBB values of the compounds were found to be central nervous system (CNS)-inactive (Chen et al., 2021). Furthermore, skin permeability values of the compounds 3a-j were observed as À1.67, À1.64, À1.52, À1.61, À0.85, À1.55, À1.65, À1.41, À1.15, and À0.74 cm/s, respectively. The log P values from À3 to þ6 ensure the compounds have good absorption by the skin (Viana Nunes et al., 2020). According to the results, it was noted that all compounds have good absorption via the skin. In addition, the toxicity risk parameters were also calculated. The compounds were observed as mutagen except for 3e and 3j. The carcinogenicity mouse and rats were found to be negative. The hERG inhibition of the compounds demonstrated low risk except for compounds 3d, 3e, 3 h, 3i, and 3j.
Absorbed percentage human intestinal absorption (HIA) from 0 to 20% are poor, from 20 to 70% are moderate, from 70 to 100% are high.
The compounds were calculated with low cell permeability (from 0.0298 to 3.4342 nm/s) for the MDCK. It has been reported that the bounding plasma protein bind (PPB) values < 90% are poor, and values > 90% are strong (Moussa et al., 2018). The observed results uncovered that all compounds'  plasma protein bind (PPB) values exhibited strongly bounding (92-100). As a result, obeying Lipinski's rule of five, drug-likeness, physicochemical properties, and toxicity risk parameters of compounds 3a-j were concluded to suitably predict pharmacokinetic values. In brief, the compounds can be drug candidates. The Molinspiration software was utilized for the physiological properties of the naphthalene-based sulfonate derivatives 3a-j, and the resulting data are exhibited in Table 9. The rule of five for drug-likeness properties of the compounds was suitable (less than five octanal-water partition coefficient (milogP) except compounds 3d, 3e, 3 h, 3i, and 3j the molecular weight (M.W) less than 500 g/mol, less than five hydrogen bond donors (HBD), less than ten hydrogen bond acceptors (HBA), and less than ten rotatable bonds (nrotB). It was known that conventional oral drugs have topological polar surface areas (TPSA)of less than 140 Å (Whitty et al., 2017). According to preADMET studies, it was determined that TPSA values of compounds 3a-j were less than 140 Å, meaning that they are similar to the drug-likeness. So, the compounds 3a-j can be used as potential drug molecules relating to the drug-likeness.

Conclusıon
In this study, targeted naphthalene-based sulfonate derivatives were prepared by utilizing a TEA-mediated mild reaction process. Based on the obtained results, it was observed that naphthalene-based sulfonate derivatives showed suitable inhibitory activities against tyrosinase and pancreatic lipase enzymes compared to the standard inhibitors. Briefly, the enzyme assays showed that three of the synthesized compounds (3a, 3c, and 3d) had more effective inhibitions against the tyrosinase enzyme, whereas three other compounds (3e, 3 h, and 3j) had more effective inhibitions against the pancreatic lipase. The naphthalene-based sulfonate derivatives exhibited different effects on enzyme active sites owing to the interactions of different substituent groups. Based on the result of preADMET studies, it was observed that all compounds showed high HIA (70-100%) values. These values indicate that the compounds can be well absorbed for oral administration. The carcinogenicity mouse and rats were observed to be negative. Specifically, the hERG inhibition of the compounds 3a, 3 b, 3c, 3f, and 3 g demonstrated low risk. Furthermore, by establishing strong electrostatic interactions, such as hydrogen bonding and p-p stacking, a consistent charge distribution was found to be effective in contributing to the experimentally determined enzyme inhibition potential of the studied compounds against pancreatic lipase and tyrosinase. As a result, it can be said that these compounds can be used in in vivo studies and later as drugs.