Triterpenes from the roots of Lantana montevidensis with antiprotozoal activity

Abstract

Bioassay guided fractionation of the roots of Lantana montevidensis (Verbenaceae) has resulted in the isolation and identification of three new triterpenoids; 13β-hydroxy-3-oxo-olean-11-en-28-oic acid (1), 12β,13β-dihydroxyolean-3-oxo-28-oic acid (2) and12β,13β,22βtrihydroxyolean-3-oxo-28-oic acid (3) in addition to nine known compounds: oleanonic acid (4), oleanolic acid (5), 3β,25β-dihydroxy-olean-12-en-28-oic acid (6), lantadene A (7), 19α-hydroxy-3-oxo-olean-12-en-28-oic acid (8) pomolic acid (9), camaric acid (10) together with β-sitosterol (11) and β-sitosterol-3-O-β-ᴅ-glucoside (12). The structures of the isolated metabolites were elucidated based on comprehensive 1D and 2D NMR spectroscopic data as well as HR-ESI-MS. The extracts and the isolated metabolites were evaluated for their antiprotozoal and antimicrobial activities. Compound 2 showed antibacterial activity against Staphylococcus aureus and methicillin resistant Staphylococcus aureus with IC 50 values against both organisms of 2.1 μM and compound 10 showed activity against same organisms with IC 50 values 8.74 and 8.09 μM, respectively, compared to the positive control Ciprofloxacin (IC 50 =0.3Μm against Staphylococcus aureus and MRSA). Compounds 1, 4, 5, 6, and 10 showed moderate antileishmanial activity with IC 50 values ranging between (5.74-14.95 μM) and IC 90 values ranging between (11.90-19.47 μM), using Pentamidine as a control (IC 50 values 2.09->16.8 μM) and IC 90 values ranging between (4.72->16.8 μM). These compounds also showed highly potent antitrypanosomal activity with IC 50 values ranging between (0.39-7.12 μM) and IC 90 values ranging between (1.91-8.13 μM), which are more efficient than the DFMO, the antitrypanosomal drug employed as positive control (IC 50 and IC 90 values 11.82 and 30.82 μM).

Phytochemical study of Piliostigma thonningii, a medicinal plant grown in Nigeria

“…Difluoromethy lornithine was used as positive drug controls. IC 50 values were computed from the dose response growth inhibition curve by XLfit version 5.2.2 (Mohamed et al 2016a; Tarawneh et al 2018). …”

“…A representative crucial metabolite isolated from P. thonningii is D-3- O -methylchiroinosital, which possesses anthelmintic activity (Asuzu et al 1999), analgesic, antipyretic, antidiabetic, antioxidant, and antilipidemic activities (Asuzu and Nwaehujor 2013; Nwaehujor et al 2015); another potential example is C-methyl flavanols, which was identified from the same species and showed antibacterial and antiinflammatory activities (Ibewuike et al 1997). In continuation to our studies on African medicinal plants (Afolayan et al 2018; Mohamed et al 2016a, 2017, 2016b; Mostafa et al 2016), and based on our in-house battery of screening, we have perused leishmanial and trypnasomal studies on the chemical constituents of P. thonningii. …”

1H and 13C NMR reassignment of some chemical shifts of lantanilic acid and camaric acid

“…The chemical shifts and their assignments reported by Siddiqui are summarized in Table . Years after this work, more studies have been conducted on 1 and 2 , and they refer to Siddiqui's article for spectral assignments . However, our analysis indicated that eight signals were wrongly assigned.…”

“…Years after this work, more studies have been conducted on 1 and 2, and they refer to Siddiqui's article for spectral assignments. [6][7][8][9][10][11][12][13][14][15][16] However, our analysis indicated that eight signals were wrongly assigned.…”

Recent Advances on anti-MRSA Natural Products Derived from Plants

“…[14] 5,3-Dihydroxy-5-(3-hydroxy-3-me- (27) and yukovanol (28) also showed strong inhibitory effects on it. [16] Bioassay-guided screening resulted in the isolation of compound 2,4-dihydroxychalcone (29) by Ahmat et al, which exhibited the antibacterial activity with MIC value of 100 μg/mL against MRSA.…”