Isolation of lupeol from Grewia lasiocarpa stem bark: Antibacterial, antioxidant, and cytotoxicity activities

Abstract

Abstract. Akwu N, Naidoo Y, Singh M, Thimmegowda SC, Nundkumar N, Lin J. 2020. Isolation of lupeol from Grewia lasiocarpa stem bark: Antibacterial, antioxidant, and cytotoxicity activities. Biodiversitas 21: 5684-5691. Lupeol a pentacyclic triterpenoid, was extracted from the stem bark of Grewia lasiocarpa. Stem bark was macerated with chloroform (CHCl3) at 25 ± 2°C, and then purified using a silica gel column. The mobile phase was hexane (100%) and hexane: ethyl acetate (80:20) as the mobile phase. The structure of lupeol was identified by 1HNMR, and 13C NMR spectral data, compared with reported data. The antibacterial, antioxidant and cytotoxicity activities of lupeol were evaluated using agar-well diffusion against six clinic bacteria isolates, namely Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC 314588), and Salmonella typhimurium (ATCC 14026) Gram-positive bacteria: Staphylococcus aureus (ATCC 25923), methicillin-resistant Staphylococcus aureus (MRSA) (ATCC BAA-1683). The antioxidants assays were performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). Cytotoxicity activity was carried out by MTT (3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium bromide) assay was carried out against HEK293 (human embryonic kidney), HeLa (cervical carcinoma), and MCF-7 (breast adenocarcinoma) cell lines. The concentration range of lupeol was 240-15 µg/mL. Lupeol at the concentration of 240 and 120 µg/mL have no antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) (ATCC BAA-1683). The antioxidant activity was dose-dependent, while cytotoxic activities were observed in HEK293, HeLa, and MCF-7 cells. This study was the first report on the extraction, isolation, and biological activities of lupeol, from the stem bark of G. lasiocarpa.

The Chemical Composition and Health-Promoting Effects of the Grewia Species—A Systematic Review and Meta-Analysis

“…As shown in Table 1, a wide variety of extracts/solvents and techniques were reported in the literature. In detail, 25.2% of the compounds were extracted with methanol in six studies [14,[21][22][23][24][25], 47.8% with acidified methanol in two studies [13,26], 11.7% with water in two studies [2,27], 5.04% with 50% methanol in one study [24], 4.20% with petroleum ether in one study [28], 3.36% with chloroform in two studies [15,29], 2.52% with ethyl acetate in one study [2], 1.68% with aqueous acetone in one study [30], and 1.68% with 80% methanol in one study [8]. Mass spectrometry was the most commonly employed technique for the identification of bioactive compounds (81.5%) wherein one study used ESI-MS/MS, one used LC-QToF-MS, one used GC-MS, and two used NMR spectroscopy.…”

“…Regarding the plant parts analyzed in each study, the fruits of G. asiatica were the most explored, with five articles studying fruits alone [2,13,21,24,26,30]. Two articles focused on G. asiatica leaves [8,41], two explored G. asiatica flowers [29,42], one studied Grewia optiva leaves [27], one studied G. asiatica stems [28] and each studied G. microcos [37] and G. lasiocarpa stems [15], G. tiliaefolia bark [22], G. hirsute leaves [23], and G. optiva roots [14] and stems [25] to identify the phytochemical constituents.…”

“…Eight categories of secondary metabolites were studied in fruits, four in stem bark, three in flowers, three were reported in leaves, and one in pomace. Out of 19 stud-ies, only 3 performed the quantitative analysis [8,13,26] whereas 16 articles without quantitative information of bioactive metabolites were reported [2,14,15,[21][22][23][24][25][27][28][29][30]37,[40][41][42].…”

“…Eleven studies investigated the antioxidant potential of the Grewia species; eight of them studied G. asiatica [1,24,[46][47][48][49][50][51], one article focused on G. optiva [27], one evaluated G. lasiocarpa [15], and one appraised both G. flava and G. biocolor [52]. The scavenging and reducing potential of various parts of the Grewia species was reported to be dose dependent.…”

“…They are also reported to hold immunomodulatory potential, to ameliorate learning and memory deficits, and to be effective against neurodegenerative ailments [10][11][12]. Such effects are predominantly attributed to the synergistic effects of phenolics such as flavonoids (i.e., flavones, flavanones, isoflavonoids, flavanols, dihydroflavonols, tannins, anthocyanidins), triterpenes, alkaloids, and phytosterols that are abundantly available in these species [2,[13][14][15].…”