Phytochemical Investigation and in vitro Antimicrobial and Antioxidant Activities Evaluation of Erianthemum aethiopicum Wiens and Polhill.

Background: Erianthemum aethiopicum Wiens and Polhill (Loranthaceae) is a parasitic plant native to north eastern Africa and Ethiopia. In Ethiopia, it is traditionally used to treat breast swelling, mastitis, morning illnesses and vomiting. Objective: This study aimed to screen the main phytochemical constituents; determine the total amounts of phenolics, flavonoids, and tannins; and evaluate the antimicrobial (against Escherichia coli, Staphylococcus sciuri, Candida glaebosa and Cryptococcus albidus) and antioxidant (against DPPH radical and ferric ion) activities of E. aethiopicum leaves extracts. Methods: Powdered E. aethiopicum leaves were macerated using n-hexane, chloroform, ethyl acetate, ethanol, and methanol. All crude extracts were qualitatively screened for phytochemical identification. The total phenolic, flavonoid, and condensed tannin contents of the chloroform, ethanol, and methanol extracts were determined by UV-Vis spectrophotometry. The n-hexane, chloroform, and methanol extracts were evaluated for their antimicrobial activity against the aforementioned microbes using agar disc diffusion and broth micro-dilution techniques. Chloroform, ethanol, and methanol extracts were also evaluated for antioxidant activity by DPPH and ferric ion reduction antioxidant power (FRAP) assays. Results: Methanol (17.56 ± 16%) and ethanol (16.45 ± 19%) showed better extraction efficiency. Flavonoids, polyphenols, tannins, terpenoids, saponins, and sterols were detected in all extracts. The highest total content of phenolics (22.63 ± 0.69 mgGAE/gDCE), flavonoids (5.38 ± 0.52 mgCE/gDCE) and tannins (39.18 ± 38 mg CE/g DCE), as milligram of gallic acid and catechin per gram of dried crude extract, were recorded in the methanolic extract. The methanolic extract also presented best anti -DPPH strength (IC50, 4.31 µg/mL) and ferric ion reduction power (absorbance of 0.71) though found weak compared to the ascorbic acid (IC50 of 0.49 µg/mL and absorbance of 0.93, respectively). Conclusion: All evaluated extracts displayed antifungal activity against both Cryptococcus albidus and Candida glaebosa strains (minimum inhibitory concentration values of 12.5-25 mg/mL), whereas they were found to have negligible activity against all tested bacterial strains. This report provides preliminary information for further phytochemical investigation of Erianthemum aethiopicum to isolate potential antioxidant and antifungal compounds.

Isolation and identification of endophytic bacteria and associated compound from Gloriosa superba and their antibacterial activities.

Gloriosa superba L., which belongs to the genus Gloriosa and family Colchicaceae, is a climbing annual herb and tuberous poisonous tropical medicinal plant. This study was aimed to isolate possible endophytic bacteria from leaves, stems and tubers of Gloriosa superba. Thirty pure endophytic bacteria were isolated and subjected to biochemical characterization. Bacterial identification was conducted by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The structure of the isolated compound was characterized. The antibacterial activity was also evaluated. Majority (21, 70 %) of the isolates were Gram-positive. Certain of them are spore formers. Based on MALDI-TOF MS, 26 of the isolates were identified as Bacillus spp. (65.4 %), Escherichia spp. (30.8 %) and Providencia spp. (3.9 %). A 1-undecene was isolated from culture filtrate of E. coli (GST-5). The ethyl acetate extracts (1000 µg/mL) of GSL-5 and GST-2 culture filtrates recorded maximum inhibition zone against E. coli (9.4 ± 0.6 mm) and S. aurous ATCC 25923T (8.4 ± 0.8 mm), respectively. The Pseudomonas aeruginosa ATCC 27853T was prone to all ethyl acetate extracts. A 1-undecene showed a moderate activity against E. coli ATCC 25922Tand P. aeruginosa ATCC 27853T at 50 µg/mL. The present finding would be a breakthrough to studies of similar works in Ethiopia since it may be for the first time.

Compounds with antibacterial and antioxidant activities from Cadia purpurea.

Five compounds 1-5 were reported from leaves and roots of Cadia purpurea herein. 2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-17-(1-hydroxypent-4-en-2-yl)-10,13-dimethyl-1H-cyclopenta[a]phenanthren-3-ol (1), apigenin-7-O-rhaminoglucoside (2) and 13-O-pyrrolecarboxyl lupanine (3) were isolated from chloroform and methanol leaves extracts. And 5-((trihydro-2-oxy-4-(hydroxymethyl)-5-(3-hydroxyphenyl)furan-3yl)methyl)benzene-1,2,3,4-tetraol (4) and bis(2-hydroxybutyl) phthalate (5) were isolated from the chloroform: methanol (1:1) roots extract. The structures of the compounds were characterized using NMR, IR and GC/MS spectroscopic data. In vitro antibacterial and antioxidant activities of leaves extracts and compounds 1, 2, 4, and 5 were also evaluated. The present findings disclosed that tested compound isolates and extracts showed dose-dependent antibacterial and antioxidant activities. The molecular docking result indicates that isolated compounds show no violation of the Lipinski's rule of five. Compounds 1, 2, 4, and 5 were reported herein for the first time from the leaves and roots of C. purpurea. Further biochemical investigation on whole parts of the plant may uncover additional chemical entities with better biological activities.

In Vitro Antibacterial and Antioxidant Activities and Molecular Docking Analysis of Phytochemicals from Cadia purpurea Roots.

Phytochemicals and antibacterial and antioxidant activities of Cadia purpurea roots were investigated herein for the first time. The phytochemical study led to the isolation of two compounds, di-(2-methylheptyl) phthalate (1) and 13-O-pyrrolecarboxyl lupanine (2), from methanol roots extract of C. purpurea. The antibacterial activity results revealed that the n-hexane extract presented a better inhibitory value (13.8 ± 0.0 mm) followed by chloroform (11.1 ± 0.4 mm) and chloroform : methanol (1 : 1) (10.7 ± 0.1 mm) extracts against E. coli at the maximum dose of 100 mg/mL. While, methanolic and ethanolic extracts displayed a mild activity against same bacterium at same dose. The methicillin resistant S. aureus was found with almost total resistance to all extracts up to the 100 mg/mL. The chloroform : methanol (1 : 1), chloroform, and n-hexane extracts recorded inhibition zone values (8.0 ± 0.0-10.0 ± 0.1 mm, 7.7 ± 0.0-9.8 ± 0.1 mm, and 7.3 ± 0.2-8.9 ± 0.2 mm, respectively) better than chloramphenicol (7.2 ± 0.6 mm at 30 µg dose) against P. aeruginosa. The alcoholic extracts also exhibited an activity better than chloramphenicol up to 25 mg/mL against same bacterium. Compound 2 produced a comparable inhibition value (9.6 ± 0.0 mm to 18.5 ± 0.0 mm) to that of chloramphenicol (21.5 ± 0.3 mm) against E. coli at doses up to 1.0 mg/mL; whereas, compound 1 showed a slight activity (7.1 ± 0.1 mm-10.3 ± 0.0 mm). Both compounds were found generally inactive against S. aureus, while they provided an activity better than chloramphenicol (7.2 ± 0.6 mm) against P. aeruginosa with inhibition zones ranging from 7.1 ± 0.0 mm to 9.0 ± 0.1 mm for compound 1 and 7.2 ± 0.0 mm to 10.6 ± 0.0 mm for compound 2. Ethanolic and methanolic extracts exhibited a better DPPH radical scavenging activity (IC50 values of 12.9 and 16.03 µg/mL, respectively) and strong ferric ion reducing power (with absorbance of 0.788 ± 0.000 and 0.810 ± 0.001, respectively) at a concentration of 500 µg/mL compared to the other extracts. Compound 1 also possessed a better anti-DPPH trapping activity (IC50, 7.99 µg/mL) than compound 2 (IC50, 58.34 µg/mL). The compounds, however, indicated a weak ferric ion reduction power even at higher amount. In general, the observed antibacterial and antioxidant activities of isolated compounds and extracts were found to be dose-dependent. Conducting further biochemical investigations on all parts of this plant could provide opportunities of finding extra alkaloidal compounds and other phthalate derivatives with better biological activity.