Allelopathic Potential of Lantana camara L. Leaf Extracts and Soils Invaded by It on the Growth Performance of Lepidium sativum L

Lantana camara is a noxious invasive plant that invades agricultural and natural ecosystems. In the current study, phytotoxicity of hexane and ethanolic leaf extracts of L. camara in different concentrations and soils invaded by it on Lepidium sativum were investigated under laboratory conditions. Soil toxicity was evaluated by comparing the growth of L. sativum on soils sampled from Lantana-invaded and Lantana-free sites. Results showed that extract concentrations and solvent type and their interaction significantly reduced percent seed germination and seedling growth. Compared to control (distilled water), both hexane and ethanol extracts at 5% w/v concentration significantly reduced percent germination and early seedling growth and completely inhibited seed germination at 10% w/v of hexane leaf extract, suggesting that hexane extract has a greater inhibitory effect than ethanolic extract in all the parameters measured. However, growth performance and seed yield of L. sativum grown on soil invaded by Lantana did not significantly vary from those grown on soils sampled from noninvaded sites. The results of this study generally showed that though Lantana leaf extracts have a direct negative allelopathic effect on L. sativum, soils invaded by Lantana have no toxic materials in the soil to directly or indirectly inhibit the growth of L. sativum. Further field studies on allelopathic effects of Lantana on L. sativum are recommended.

Population Structure and Regeneration Status of Woody Plant Species in Tulu Korma Dry Afromontane Forest, West Shewa Zone, Oromia, Ethiopia

A study was conducted on Tulu Korma afromontane forest to assess woody plant species' population structure and natural regeneration status. Data were collected from 52 main quadrats of 400 m² for mature woody species and 260 subplots of 25 m² for seedlings and saplings. All live woody plant species were recorded with their densities, heights, and DBH. Frequency, basal area, importance value, and Shannon-Wiener diversity indices were computed. A total of 101 species that belonged to 45 families were documented. Diversity and evenness indices were 3.44 and 0.7, respectively. Combined density of woody species of all developmental stages was 4971 stems ha^-1 of which 39, 32, and 28% were with DBH < 3.5 cm (seedlings), between 2 and 10 cm (saplings), and >10 cm (mature wordy species), respectively. The total basal area of individuals with DBH ≥ 3.5 cm was 116.18 m² ha^-1. Olea europaea and Podocarpus falcatus were the most dominant species. About 41.58% of the species had IVI < 1. Population structure based on combined densities revealed that density of seedling > sapling > mature individuals, suggesting healthy population structure and good regeneration. On individual basis, however, species showed different patterns of population structure of which 12, 51, and 37% species showed good, fair, and poor regenerations, respectively. Species with least IVI and poor regeneration should be given conservation priority.

Effect of Extraction Solvents on Total Polyphenolic Content and Antioxidant Capacity of Syzygium Aromaticum L. Flower Bud from Ethiopia

In this study, the antioxidative activity and polyphenolic content of Syzygium aromaticum's flower bud were compared under different extraction solvents including chloroform, ethyl acetate, methanol, and aqueous. The antioxidant activity was assessed via established in vitro assay models such as 2, 2-diphenyl-1-Picrylhydrazyl (DPPH) radical scavenging assay, NO- radical scavenging assay, H2O2 scavenging assay and Fe3+ reducing capacity. Total phenolic content was measured according to Folin-Ciocalteu's method, and total flavonoid content was estimated by using the aluminum chloride colorimetric method. The results showed that aqueous extract possessed the highest TPC (19.11 ± 2.76 mg GAE/g DW) and TFC (15.32 ± 1.53 mg CtE/g DW). Among the extracts, methanol extract exerted the strongest radical DPPH quenching activity with an IC50 value of 303.56 ± 13.14 μg/mL. The highest NO- radical scavenging activity was shown by methanol extract (IC50192.94 ± 1.9 μg/mL) which is stronger than BHT (IC50247.64 ± 12.89 μg/mL). Methanol extract showed a strong H2O2 scavenging activity (IC50233.71 ± 3.72 μg/mL). The highest Fe3+ reducing capacity was shown by methanol extract (Absorbance = 0.36 ± 0.05). Strong and positive correlations were observed between total phenolic and flavonoid contents and the antioxidant assays. The results of the present work revealed that the tested spice demonstrated high antioxidant activity, total phenolics, and flavonoids. Thus, this spice is worth considering as important source of natural antioxidant agents.

In vitro antioxidant activity of banana (Musa spp. ABB cv. Pisang Awak)

The methanolic extract of Musa ABB cv Pisang Awak was investigated for the polyphenolic contents and antioxidant activity. The total phenol and flavonoid contents of the fruit extract were found to be 120 mg gallic acid equivalents (GAE) and 440 mg quercetin equivalents (QE)/100 g of sample dry weight, respectively. The antioxidant activity of the Pisang Awak methanol extract (PAME) (20-500 microg/ml) was determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, reducing capacity, 2-2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) radical cation decolourization and hydroxyl radical scavenging capacity (OH*). The EC50 values of DPPH, ABTS and OH* activities of the PAME and butylated hydroxy toluene (BHT) were found to be 65 and 9 microg/ml, 29 and 6 microg/ml, 36 and 42 microg/ml respectively. The reducing capacity increased with increasing concentration (31.5-1000 mg/ml) of the fruit extract and the activity was comparable with the standard BHT. The high performance thin layer chromatography (HPTLC) analysis of the extract revealed the presence of polyphenols. The strong and positive correlations were obtained between total phenol/flavonoid contents (R2 = 0.693-1.0) and free radical scavenging ability was attributed to the polyphenols as the major antioxidants.

Antioxidant activities of bark extract from mangroves, Bruguiera cylindrica (L.) Blume and Ceriops decandra Perr

OBJECTIVES

The antioxidant activities of two Indian mangrove plants, Bruguiera cylindrica and Ceriops decandra, were investigated.

MATERIALS AND METHODS

Total phenolics and total flavonoid contents of the mangroves were determined using folin-ciocalteu reagent method and aluminium chloride method, respectively. Antioxidant capacity was assessed by the following methods: 1,1-diphenyl-2-picryl hydroxyl (DPPH.) quenching assay; 2,2'- azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS.(+)) cation decolorization test; scavenging capacity towards hydroxyl ion radicals (.OH); reductive capacity; and antihemolytic activity.

RESULTS

The mangroves yielded 233.3 ± 0.062 and 283.31 ± 0.04 mg gallic acid equivalent/g phenolic contents and 11.6 ± 0.12 and 15.1 ± 0.02 mg quercetin equivalent/g flavonoid contents. The methanol extracts of both mangroves exhibited high antiradical activity against DPPH., ABTS.(+), and .OH radicals. The reductive capacity of the extracts increased with increasing concentration of samples. The extracts also inhibited H(2)O(2) induced hemolysis in cow blood erythrocytes. The antioxidant activities were found stronger than that of the reference standard, butylated hydroxy toluene (BHT). The antioxidant activity of mangrove plants was correlated with total phenolics and flavonoid contents.

CONCLUSION

Both plants can be considered as good sources of natural antioxidants for medicinal uses. Further studies are necessary to isolate active principles responsible for the overall antioxidant activity of the extracts.

In vitro antioxidant activity of Hedyotis corymbosa (L.) Lam. aerial parts

The methanolic extract of the aerial part of Hedyotis corymbosa (L.) Lam. (Rubiaceae) was screened for antioxidant activity using 1,1-diphenyl-2-picryl hydroxyl (DPPH) quenching assay, 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) cation decolorization test, ferric reducing power (FRP), scavenging capacity towards hydroxyl ion (OH*) radicals and nitric oxide (NO) radical inhibition activity using established assay procedures. Total phenolics and total flavonoid contents were, also determined. The plant yielded 210 mg gallic acid equivalent/100 g phenolic content and 55 mg quercetin equivalent/100 g flavonoid content. The extract exhibited high antiradical activity against DPPH, ABTS, nitric oxide and hydroxyl radicals with EC50 value of 82, 150, 130, and 170 microg/ml, respectively. The FRP increased with increasing concentration of the sample. The antioxidant activity of the extract was comparable with that of the standard butylated hydroxyl toluene (BHT). High correlation between total phenolic/flavonoid contents and scavenging potential of different reactive oxygen species (R2 = 0.785-0.998) indicated the polyphenols as the main antioxidants.

In vitro antioxidant and antibacterial activity of Rhaphidophora pertusa stem

Methanol extract of Rhaphidophora pertusa stem was analyzed for its antioxidant (DPPH, reducing power and Fe(3+) metal chelation methods) and antibacterial activities. The extract was found effective against the three antioxidant test models and exhibited strong and moderate antibacterial activity against the tested pathogenic bacteria.

Hepatoprotective studies on Hedyotis corymbosa (L.) Lam

Hedyotis corymbosa is used in traditional medicine of India and China to treat various hepatic disorders. In the present study, the hepatoprotective effect of the methanolic extract of the whole plant of Hedyotis corymbosa against paracetamol overdose-induced liver damage in Wistar rats was studied. The methanolic extract of the plant produced significant hepatoprotective effects as evidenced by decreased serum enzyme activities, SGPT, SGOT, SAKP and serum bilirubin and an almost normal histological architecture of the liver, in treated groups, compared to the controls. Hedyotis corymbosa shortened hexobarbitone-induced sleeping time in mice, besides showing significant antilipid peroxidant effect in vitro. The results thus support the use of Hedyotis corymbosa as a hepatoprotective agent.

Antibacterial activity of Eupatorium glandulosum leaves

Antibacterial screening of petroleum ether, chloroform, ethyl acetate, methanol and aqueous extracts of Eupatorium glandulosum leaves exhibited a broad spectrum of inhibitory activity against Gram (+) and Gram (-) pathogenic bacteria.