ABSTRACT
In this study, five Egyptian species were tested for their In vitro antimicrobial activities. The antimicrobial screening was carried out via disc diffusion method toward four strains of the clinical antibiotic resistant pathogens including Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus niger. Among the methanolic extracts screened, Azadirachta indica, Tectona grandis and Ficus sycomorus showed a broad antimicrobial spectrum against three strains with inhibition zones between 13-27 mm followed by Gmelina arborea and Ficus microcarpa with inhibition zones between 11-17 mm, all plants showed no activity against Aspergillus niger except Gmelina arborea with inhibition zones 12 mm. Penicillin G was used as positive control at concentration of 100 μg/disc with inhibition zones (Staphylococcus aureus 28mm, Escherichia coli 22mm, Candida albicans 25mm and Aspergillus niger 0mm). Owing to the high activity of the methanolic extracts, these extracts were defatted via petroleum ether then were fractionated via; chloroform, ethyl acetate and n-butanol. The n-butanol of Azadirachta indica was the most active against Candida albicans (25 mm), ethyl acetate of Ficus sycomorus against Staphylococcus aureus (18 mm), n-butanol of Gmelina arborea against Staphylococcus aureus (17 mm) and n-butanol of Ficus microcarpa against Staphylococcus aureus (15 mm). These results suggest that the tested plants may be effective potential sources of natural antimicrobials, and are potent inhibitors of antibiotic resistant pathogens.
ABSTRACT
Aims: The leaves of Gmelina arborea (ROXB.) (Family Verbenaceae) are widely used in the folklore to treat various types of diseases. In this study, the antioxidant and cytotoxic activities of different methanolic extracts and the derived subfractions of 90% methanolic extract of this plant were evaluated. Methodology: The antioxidant activity was carried out via three different quantitative assays as well as qualitative one. Total phenolic was determined via Folin-Ciocalteu and total flavonoid via AlCl3 assays. The cytotoxic activity was carried out via brine shrimp test and toward human cancer cell line; HepG2 using Sulphorhodamine-B assay. The 90% methanolic extract was fractionated using pet. ether then the 90% defatted methanol undergoes fractionation using (CHCl3, EtOAc and n-BuOH). Results: The antioxidant results showed that the; DPPH antioxidant activity was (19.20, 14.10 and 28.94 μg/ml); total antioxidant capacity was (412.69, 518.45 and 390.41; mg AAE /g extract); reducing power was (0.649, 0.715 and 0.396; 200 mg/ml) and total phenolic was (330.22, 400.66 and 244.76; mg GAE/g extract), respectively for 90% methanol, n-BuOH and EtOAc. The cytotoxic results showed that the; mortality of brine shrimp larvae (LC50) against different dosages of defatted 90% methanol, n-BuOH and EtOAc respectively was (158.48, 39.81 and 199.52; μg/ml) and the results of HepG2 assay showed that n-BuOH fractions have cytotoxic activity with IC50 ≤ 20 μg/ml (IC50 = 17.3 μg/ml) which falls within the American Cancer Institute criteria followed by 90% methanol and EtOAc (IC50 = 22.1 μg/ml). Conclusion: It was concluded that Gmelina arborea extracts possess a powerful antioxidant and cytotoxic activities.