## 4 Discussion
The antibacterial and anti-viral activity may be due to the presence of bioactive compounds identified by GC-MS, such as D-threitol [47], 2-methoxy-4-vinylphenol [48], \(\gamma\)-sitosterol [45; 49], thiodiglycol [50], 4-fluoroaniline [51], lactose [52; 53], 14-methylpentadecanoic acid [54], D-4-C-methyl-mymo-inostic [55], 1,2-benzenedicarboxylic acid [56; 57], and 2-hydroxyhexadecanoic acids [58]. The ethanolic extract of _Z. pentandra_ showed a dose-dependent effect and significant zone of inhibition (average greater than 8 mm) against gram-negative and gram-positive strains of bacteria. Previously, methanolic extract was tested for antibacterial activity against _E. coli_, _S. typhi_, _B. spizizieni_, _S. aureus_, and _S. epidermidis_[16]. The inhibition of the carbohydrate digestion enzyme (\(\alpha\)-glucosidase) is helpful in reducing the cleavage of complex carbohydrates (from oligosaccharides to monosaccharides), thus preventing hyperglycemia [29; 59]. A total of eight bioactive compounds were identified from the ethanolic extract of _Z. pentandra_ by GC-MS with strong antidiabetic potential. These compounds were reported in _Z. pentandra_ for the first time; however, previously, compounds such as \(\gamma\)-sitosterol [36], 1,2-benzenedicarboxylic acid [60], dioctyl phthalate [61], 14-methylpentadecanoic acid [62], 4-fluoroaniline [63], 2-methoxy-4-vinylphenol [64], and d-threitol [65; 66] were reported in other studies. Our investigation revealed an extremely high potential of \(\alpha\)-glucosidase inhibition of ethanolic extract of _Z. pentandra_ as compared to standard (Acarbose) with IC\({}_{50}\) 10.0 \(\pm\) 0.08 \(\mu\)g/mL and 5.87 \(\pm\) 0.01 \(\mu\)g/mL, respectively. The biosynthesis of melanin can be regulated by tyrosinase, which will lead to melasma and age spots. Tyrosine inhibitors have a crucial role in skin protection, prevent hyperpigmentation, and are used in skin whitening products [67]. Natural tyrosinase inhibitors are considered safer and more economical, with high therapeutic activity and good skin penetration ability. Out of twenty-nine tentative compounds identified by GC-MS analysis, nine have been reported previously in other plants with potential tyrosinase inhibitory effects. The literature revealed that cyclohexane carboxamide [60], \(\gamma\)-sitosterol [68], 1,2-benzenedicarboxylic acid [69], lactose [70], dioctyl phthalate [71], 4-fluoroaniline [72], 2-methoxy-4-vinylphenol [73], and d-threitol [74] have tyrosinase inhibition activity due to strong binding with the tyrosinase enzyme. The result of our study supports the literature by showing exceptional tyrosinase inhibitory activity with IC\({}_{50}\) 20.7 \(\pm\) 0.07 \(\mu\)g/mL as compared to Kojic acid (used as a standard) with IC\({}_{50}\) 1.04 \(\pm\) 0.02 \(\mu\)g/mL. Alzheimer's disease and Parkinson's disease are the two major neurodegenerative diseases with high incident rates [75]. It is estimated that by the end of 2040, neurodegenerative diseases will become the second most cause of death even surpassing cancer in aging patients. In this regard, various natural and synthetic cholinesterase inhibitors are exploited for the control and management of neurodegenerative diseases. There is substantial evidence that shows that polyphenol or phenolic contact plays a diverse/crucial role to decrease the rate of neurological disorders [76; 77]. Our study was conducted to reveal the in vitro cholinesterase inhibition potential of the ethanolic extract of _Z. pentandra_. Furthermore, five compounds reported in the literature to have neuroprotective potential were also identified by GC-MS, such as \(\gamma\)-sitosterol [78], benzaldehyde 4-methoxy- [79], 4-fluoroaniline [80], lactose [81], and dioctyl phthalate [82], which might be responsible for the acetylcholinesterase-collagenisterase inhibition activity of the extract.