The search for new antimicrobial compounds is ongoing. Its importance cannot be overemphasized in an era of emerging resistant pathogenic organisms. This study therefore investigated the phytochemical composition and antioxidant and antimicrobial activities of different citrus juice concentrates. Fruit juices of Citrus tangerine (tangerine), Citrus paradisi (grape), Citrus limon (lemon), and Citrus aurantifolia (lime) were evaluated. Antimicrobial activities against five bacterial and three fungal strains were evaluated. The results revealed the presence of alkaloids, flavonoids, steroids, terpenoids, saponins, cardiac glycosides, and reducing sugars in all the juice concentrates. DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) radical scavenging capacities varied with tangerine and grape juices having better scavenging capacities than lemon and lime juices. Grape juice was observed to have a significantly higher (P < 0.05) ferric‐reducing antioxidant potential (FRAP) value (364.2 ± 10.25 μmol/L Fe(II)/g of the extract) than the reference antioxidant, ascorbic acid (312.88 ± 5.61 μmol/L). Antimicrobial studies revealed differential antimicrobial activities against different microbial strains. Zones of inhibition ranging from 4 to 26 mm were observed for the antibacterial tests with 0–24 mm for antifungal test. Minimum inhibitory concentrations (MIC) and minimum bacteriostatic concentrations (MBC) for concentrates against bacterial strains ranged from 12.5 to 200 μg/mL. Lemon and lime juice concentrates had lower MIC and MBC values with orange and tangerine having the highest values. Minimum fungicidal concentrations ranged from 50 to 200 μg/mL. The results of this study suggest that these juice concentrates may have beneficial antimicrobial roles that can be exploited in controlling unwanted microbial growth.

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Vernonia amygdalina and Ocimum gratissimum occupy prominent positions in the diets of several Nigerian ethnic groups. This study therefore compared the phenolic content and some antioxidative activities of the ethanolic leaf extracts of these two plants. Ethanolic extracts of freshly plucked leaves were obtained using standard procedures. The phenolic content and antioxidant capacity of the vegetables were quantified in vitro. The results show that O. gratissimum contains higher amounts of total phenolics (168.5 ± 5.50 and 97.0 ± 0.01 mg gallic acid equivalents/g extract respectively) and flavonoids (126.7 ± 1.00 and 65.4 ± 4.42 mg quercetin equivalents/g extract respectively) than V. amygdalina. A dose-dependent increase in flavonol content was observed for both extracts with higher contents obtained in the O. gratissimum extract. O. gratissimum also has higher DPPH radical scavenging activity (IC 50 values of 105.7 and 111.8 µg/ml respectively) and ferric reducing antioxidant potential (FRAP) (110.0 ± 0.02 and 85.0 ± 0.01 mg Fe 2+ /g extract). O. gratissimum also had higher reducing power than V. amygdalina at the concentrations studied. Standard ascorbic acid however had higher antioxidant activity values for the DPPH, FRAP and reducing power assays. Both plant extracts reasonably inhibit lipid peroxidation at 31.4 ± 0.15% for V. amygdalina and 42.8 ± 1.00% for O. gratissimum. The results further substantiate the medicinal value of these vegetables. Consumption of these vegetables is encouraged to help militate against deleterious effects of reactive species.

Background: Tetracarpidium conophorum (TC) is a tropical plant used in ethno medicine for treating various diseases including hepatic ailments. The present study investigated the effect of methanol extract of T. conophorum seeds in rats intoxicated with CCl 4 24 h and 48 h after intoxication respectively. Methods: Thirty-five male Wistar rats were distributed equally into seven groups. Group IA (control) received distilled water and olive oil (i.p), group IIA rats were intoxicated with CCl 4 in olive oil (600 mg/kg, i.p.) only on the 8th day, while groups IIIA, IVA and VA were given 100 mg/kg of sylimarin, 250 mg/kg and 500 mg/kg of methanol extract respectively for 7 days, thereafter they were intoxicated with CCl 4 on the 8th day. Groups VIA and VIIA were intoxicated with CCl 4 on the 8th day and administered 250 mg/kg and 500 mg/kg of methanol extract of T. conophorum seeds at 1 h, 6 h, 12 h, 18 h and 24 h and the animals were sacrificed 24 h after intoxication with CCl 4. This procedure was repeated for a different set of thirty-five (groups IB-VIIB) male rats but the animals were sacrificed 48 h after intoxication with CCl 4. Fasting blood sample was collected by cardiac puncture for biochemical analyses. Results: There were significant increases (p˂0.05) in serum hepatic enzyme markers (ALT, AST, ALP, and γ-GT) activities, as well as bilirubin and significant reduction in antioxidant enzymes (P˂0.05) in rats intoxicated with CCl 4 when compared to control group, but administration (pre-treatment and post-treatment) of methanol extract of T. conophorum seeds at doses of 250 and 500 mg/kg body weight and standard sylimarin drug attenuated the toxic insult of CCl 4 in a dose-dependent manner at 24 h and 48 h after intoxication respectively. Conclusions: Our findings confirm that methanol extract of TC exhibited hepatoprotective activity against CCl 4 induced liver damage.

Based on local claims on the efficacy of Aframomum melegueta (alligator pepper) and Costus afer (ginger lily) in the treatment of malaria, the present study compared the antioxidant activity and phytochemical constituents of extracts of A. melegueta and C. afer leaves. Methanol extracts of the plant leaves were obtained using standard procedures. The antioxidant property of the plants extracts were evaluated using DPPH (1,1-diphenyl-1-picryl-hydrazyl) radical, Total Phenol Content (TPC), Total Flavonoid Content (TFC), Proanthocyanidin Content (PC), Ferric acid Reducing Antioxidant Potential (FRAP) and ThioBarbituric Acid Reducing Substances (TBARS) assay. The phytochemical screening test revealed the presence of alkaloids, reducing sugars, flavonoids, tannins, saponins, steroids, cardiac glycosides and terpenoids in both extracts. The antioxidant study showed that the A. melegueta extract had higher DPPH radical scavenging ability (IC 50 of 122.25ug/ml), FRAP (35.38µmol Fe(II)/g) and TBARS (% inhibition of 62.08%) than C. afer (IC 50 of 156.48ug/ml, 12.25 µmol Fe(II)/g, and 42.5%, respectively). The C. afer extract, however, recorded higher levels of TFC, PC and a lower TPC content when compared with the A. melegueta counterpart. The results suggest that C. afer and A. melegueta extracts could serve as free radical scavengers, acting as primary antioxidants. The results support local claims of their therapeutic uses in the treatment of malaria in folklore medicine.