Antioxidant and Antimicrobial Studies of Some Hemi-parasitic West African Plants

Abstract

The study investigated the antioxidant and antimicrobial activities of some West African hemi-parasitic plants, which comprised Tapinanthus bangwensis (TB), Tapinanthus globiferus (TG) and Globimetula braunii (GB), used in Nigerian ethnomedicine for the management of skin and other microbial infections. This was with a view to determining the most active plant extract and fraction. The leaf and stem of each plant was separately air-dried, powdered and macerated in ethanol-H20 (8:2). The extracts were subjected to in vitro antioxidant tests such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), Fe2+ chelating ability (FIC) and total antioxidant capacity (TAC) assays, with L-ascorbic acid, quercetin and ethylenediaminetetraacetic acid (EDTA) as positive controls. The antimicrobial test was carried out using micro-broth dilution method against reference strains of methicillin-resistant Staphylococcus aureus (MRSA), Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans, where ciprofloxacin and ketoconazole were the positive controls. An activity-guided fractionation approach was adopted in the study. The most active GB leaf extract was fractionated to obtain n-hexane, dichloromethane, ethylacetate, n-butanol and aqueous fractions, and were subsequently tested. The results showed that the extract of GB leaf demonstrated the highest bioactivities with inhibitory concentration (IC50) of DPPH at 31.21±1.11 µg/mL, FRAP value of 109.30±0.76 mg AAE/g, TAC value of 178.15±3.54 mg AAE/g and MIC of 5.0 – 10.0 mg/mL. The Ethylacetate fraction of GB leaf demonstrated the highest bioactivities, which were four-times, thrice and twice better than its GB leaf extract in the DPPH, TAC and antimicrobial studies respectively. The EtOAc fraction (IC50 = 8.58±1.39 µg/mL) was comparable (P > 0.05) in antioxidant activity with quercetin (IC50 = 7.72±0.88 µg/mL). The EtOAc fraction also exhibited broad-spectrum antimicrobial activity with inhibitory concentration of 1.25 mg/mL against MRSA and C. albicans. In conclusion, the extract of G. braunii leaf demonstrated considerable bioactivities and the moderately polar EtOAc fraction was the most active fraction; hence, validates the folkloric use G. braunii leaf as a remedy for microbial infections.

Antimalarial and Erythrocyte Membrane Stability Properties of Globimetula braunii (Engle Van Tiegh) Growing on Cocoa in Plasmodium berghei-Infected Mice

“…Antimicrobial and antioxidant properties of different solvent extract and fractions of G. braunii have been reported. 35,36 Apart from the antimicrobial properties of medicinal plants, their antioxidant potential is a significant feature that can be screened for antiplasmodial potential. 37,38 This antioxidant potential may be an indicator of the therapeutic mechanism of antimalarial herbs.…”

Ursane-Type Triterpenes, Phenolics and Phenolic Derivatives from Globimetula braunii Leaf

“…Three ursane-type triterpenes (1-3), three phenolics (4-6) and two phenolic derivatives (7 and 8) were isolated and identified in our study of G. braunii living on Leucena leucocephala (Fabaceae), its host, which marked the first report of these compounds in the plant and the family Loranthaceae. Previous phytochemical studies on the plant have shown the presence of tannins, phenolics, flavonoids, terpenoids and sterols [8,10], while compounds reportedly isolated include lupeol-type triterpenes (globrauneine A-F, lupeol and lupeol acetate), lactones and flavonoids (quercetin, quercitrin, rutin and avicularin), identified in the G. braunii living on Piliostigma thonningi (Fabaceae). Perhaps, this new additions to the repository of compounds in G. braunii might have occurred because of plant-host specificity, which was reported to play a critical role in the quality and quantity of constituents elicited by Mistletoes as well as its influence on their biological properties [4].…”

“…They were powdered (5.0 kg) and macerated with 25 L of EtOH-H 2 O (4:1) at room temperature for 72 h with frequent agitation. This extraction method was a follow-up process to the previous study on the plant [8]. The filtrate was concentrated to dryness in vacuo on a Heidolph RE 400 Rotary Evaporator set at 45 • C and 100 rpm.…”

“…Biological studies have shown the antioxidant, antimicrobial and cytotoxic potentials of the leaf extract and its ethyl acetate fraction [7][8][9]. The hepatic, hematologic, anti-lipidemic, oxytocic, anti-hyperglycemic and anti-cancer activities of the plant's alcoholic, aqueous and ethyl acetate extracts have also been reported [5,6,[10][11][12] with a paucity of information on its chemistry.…”

Consuming and consumed: Biotic interactions of African mistletoes across different trophic levels

“…bojeri on Reunion was attributed to the loss of its hypothetically main dispersers (flying foxes, doves, and parrots) since human colonization of the island (Albert et al, 2017). Many species of African mistletoes are being studied by ethnobotanists due to their traditional use in spiritual practices as well as increasing exploitation in officinal medicine and by herbalists as “all‐healing,” “bone‐setting,” and “fertility‐boosting” drugs (Koffi et al, 2020; Oriola et al, 2020). At the same time, due to their broad host range and tendency to spread rapidly, many mistletoe species have gained a reputation as notorious pests that cause significant losses in tree crops (Dibong et al, 2008).…”