In vitro antioxidant, antidiabetic, antiacetylcholine esterase, anticancer activities and RP-HPLC analysis of phenolics from the wild bottle gourd (Lagenaria siceraria (Molina) Standl.)

Abstract

Lagenaria siceraria is the most popular and widely used fruit vegetable due to its immense health promoting properties. The aim of the present study was to evaluate phytochemicals and biological activities of the different fruit parts (epicarp, mesocarp and seeds) of wild bottle gourd extracted with acetone, ethanol, methanol and water. Present study highlighted that seeds extracted with ethanol showed significantly higher total phenolics content (TPC) and total flavonoids content (TFC) (112.58 ± 1.39 mg TAE/g extract; 12.82 ± 0.64 mg CE/g extract, respectively). However, aqueous seeds extract had slightly higher (2.27 ± 0.05 mg CE/g extract) total tannins content (TTC) than ethanolic seeds extract. In addition, total terpenoids content (TTEC) was recorded higher in acetone seed extracts (384.19 ± 19.1 mg UAE/g extract). In antioxidant evaluation, methanolic extract of seeds exhibited considerable DPPH (2, 2-diphenyl-1-picrylhydrazyl) and ABTS (2, 2′-Azino-bis-(3-ethyl) benzothiazoline-6-sulfonic acid) radical scavenging activities (54.08 ± 0.67 mg TE/g extract and 38.58 ± 0.36 mg EE/g extract, respectively). However, ethanol and acetone seed extracts revealed significant phosphomolybdenum and FRAP (ferric reducing antioxidant property) activities (285.56 ± 3.71 and 72.32 ± 0.52 mg TE/g extract, respectively). In contrast, mesocarp extracted with water showed highest (15.17 ± 0.08 mg EE/g extract) metal chelating activity. Overall, ethanolic seed extract was found to be the excellent combination for the recovery of metabolites. Principal component analysis (PCA) revealed the discrimination of phytochemical profile and antioxidant potential of studied extracts and fruit parts. Ethanolic seed extracts exhibited appreciable α-amylase inhibition (28.96% at 1000 μg extract) and acetylcholine esterase inhibition (56.49% at 300 μg extract), however, α-glucosidase inhibition (71.85% at 300 μg extract) was highest in methanol extract. The bitter principle isolated from the seeds revealed potent anticancer activities against MCF-7 (GI50 < 10 μg/mL, TGI 133.42 μg/mL, LC50 301.21 μg/mL) and HT-29 (GI50 < 10 μg/mL, TGI 6.12 μg/mL, LC50 664.02 μg/mL) cancer cell lines. In RP-HPLC analysis, epicarp extracted with methanol showed highest hydroxybenzoic acid (72.46 ± 0.32 mg/g FW), vanillic acid (69.35 ± 0.73 mg/g FW) and coumaric acid (48.43 ± 0.52 mg/g FW). The study concluded that wild bottle gourd is an excellent source of bioactive metabolites responsible for the potent antioxidant, antidiabetic, antiacetylcholine esterase and anticancer activities. Further, extensive investigations to develop effective drug from the wild bottle gourd against such diseases is needed.