Phyto-constituents profiling of Luffa echinata and in vitro assessment of antioxidant, anti-diabetic, anticancer and anti-acetylcholine esterase activities

Luffa echinata Roxb. is one of the neglected medicinal plants. It is an important source of bioactive metabolites and used in several Ayurvedic formulations. In the present analysis, mature leaves and fruits were extracted with acetone, ethanol, acetonitrile, methanol and water. Phytochemicals like total phenolic (TPC), flavonoid (TFC), tannin (TTC), alkaloid (TAC) and terpenoid (TTEC) content were analysed. Further, antioxidant (AOX) activities like 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, 2,2′-azino-bis-(3-ethyl) benzothiazoline-6-sulfonic acid (ABTS) radical scavenging, metal chelating activity (MC), ferric reducing antioxidant power (FRAP) and phosphomolybdenum assay (PMA) were studied. Highest TPC and TFC (189.57 ± 1.9 mg TAE/g extract, 30.48 ± 0.7 mg CE/g extract, respectively) were reported from acetone extract of the leaves. Ethanolic fruit extract showed the highest TTC (13.79 ± 0.2 mg CE/g extract). Acetone and acetonitrile fruit extract revealed maximum TTEC (602.79 ± 3.5 mg UAE/g extract) and moderate TAC (19.96 ± 0.9 mg GE/g extract), respectively. In AOX, highest DPPH (50.52 ± 0.03 mg AAE/g extract) and ABTS (26.78 ± 0.03 mg TE/g extract) radical scavenging reported in methanolic extract of fruit; however, acetone extract of leaf showed highest FRAP (376.89 ± 1.95 mg Fe(II)/g extract) and PMA (326.54 ± 4.73 mg AAE/g extract). In contrast, aqueous extract of leaf and fruit revealed highest metal chelating activity (41.67 ± 0.49 mg EDTA/g extract). In anti-diabetic studies, acetonitrile extract of leaves and fruits exhibited appreciable inhibition of α-amylase (83.33%) and α-glycosidase (77.42%) enzymes. Similarly, acetyl cholinesterase (AChE) inhibition was highest in water (88.91%) and acetone (81.87%) extracts of leaf and fruits. Fruit extracts showed potent anticancer activity against breast (MCF-7) and colon (HT-29) cancer cell lines (LC50 329.36 and 385.17 µg/mL, respectively). RP-HPLC analysis revealed highest cucurbitacin B (CuB) (196.24 ± 1.4 mg/g DW), followed by cucurbitacin I (CuI) and cucurbitacin E (CuE) in the fruits (57.14 ± 4.9 and 2.03 ± 0.03 mg/g DW, respectively). RP-HPLC analysis of extracts revealed presence of gallic acid (GA), catechin (CA), vanillic acid (VA), chlorogenic acid (CHLA) and coumaric acid (COA), in which highest GA found in the fruits (1.26 ± 0.07 mg/g DW). Liquid chromatography and mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC–MS) analysis revealed presence