Fungitoxic effects of some leaf extracts against rhizopus oryzae causing tuber rot of potato

Extracts of Cymbopogon citratus, Azadirachta indica (Neem) and Ocimum gratissimum were effective in controlling the growth of Rhizopus oryzae in vitro and in vivo. Neem was found to be the best followed by C. citratus and O. gratissimum. Alcohol extracts of these plant species were more effective than water extracts in reducing the growth of the pathogen in culture and in checking rot development in potato tuber by the fungus. A. indica and C. citratus have considerable disease control potential and their extracts can be exploited as a source of pesticide of plant origin to control the soft rot in stored potato incited by Rhizopus oryzae.     

粤产紫罗勒精油的化学成分研究

水蒸气蒸馏法提取粤产紫罗勒精油,利用气相色谱-质谱联用(GC MS)技术进行化学成分分析,分离鉴定出15种化学成分,其中主要成分有芳樟醇(6.46%)、龙蒿脑(66.81%)、榄香烯(2.31%)和δ 杜松烯醇(9.13%)。     

Identification of the Chemotypes of Ocimum forskolei and Ocimum basilicum by NMR Spectroscopy

The chemotypes of Ocimum forskolei Benth and Ocimum basilicum L. growing wild in Oman have been established by ¹³C‐NMR analyses of the vegetative and floral oils of the plants. The chemotypes, estragole for O. forskolei and linalool for O. basilicum, suggested by ¹³C‐NMR fingerprinting were also confirmed by GC‐FID and GC/MS analyses. The oil of O. forskolei demonstrated better activities against bacteria and dermatophytes. The significance of the presence of estragole and linalool in the volatile oils of plants whose fragrances are traditionally inhaled, added to food, or rubbed on the skin are discussed.     

Stereoselective oxidation of racemic 1-arylethanols by basil cultured cells of <Emphasis Type="Italic">Ocimum </Emphasis><Emphasis Type="Italic">basilicum</Emphasis> cv. <Emphasis Type="Italic">Purpurascens</Emphasis>

The biotransformation of racemic 1-phenylethanol (30 mg) with plant cultured cells of basil (Ocimum basilicum cv. Purpurascens, 5 g wet wt) by shaking 120 rpm at 25°C for 7 days in the dark gave (R)-(+)-1-phenylethanol and acetophenone in 34 and 24% yields, respectively. The biotransformation can be applied to other 1-arylethanols and basil cells oxidized the (S)-alcohols to the corresponding ketones remaining the (R)-alcohols in excellent ee.     

Stimulation effect of carrageenan on enzymatic defense system of sweet basil against Cuscuta campestris infection

Sweet basil is an important medicinal plant used especially for therapeutical potentials. Sweet basil is a common host for Cuscuta campestris, which has a negative effect on infected plants. Therefore, natural friendly control of C. campestris seems to be useful. It has been shown that carrageenans can act as elicitors of plant defense responses. In this work, the effect of κ-carrageenans on protection against C. campestris and suppression of its invasion in basils were studied. Basils were sprayed with a solution of κ-carrageenan (1?g?L^?1), once a week, three times in total. Infection of basils with C. campestris was performed two days after the last carrageenan treatment. C. campestris stem and the leaves of basils were collected two weeks after C. campestris inoculation for biochemical studies. Treatment with carrageenan significantly increased shoot length and leaf area of basil and decreased C. campestris infestation by about 26%. The content of malondialdehyde, other aldehydes, hydrogen peroxide and lipoxygenase (LOX) activity increased significantly in basils parasitized by C. campestris. There were significant differences in phenylalanine ammonia lyase (PAL), catalase (CAT), superoxide dismutase (SOD) and peroxidase activity of parasitized basils by C. campestris compared with healthy basils. Carrageenan treatment of basils caused a significant increase in H₂O₂ content and the activity of PAL, CAT and SOD, but not of malondialdehyde, other aldehydes content and LOX, polyphenol oxidase (PPO) and peroxidases activity. The activated enzymatic defense system (PAL, PPO, CAT, SOD and peroxidase) in carrageenan-treated basils have a vital role in alleviating oxidative stress damage in infected plants, by removing excess reactive oxygen species and inhibiting LOX activity and lipid peroxidation that was observed in this study. Our results showed that the application of κ-carrageenan-induced beneficial effects in plants, with regard to growth stimulation and the activation of enzymatic defense system. Thus, carrageenan was recommended as a natural biostimulator for protection of plants against C. campestris.     

Extract of Ocimum canum lowers blood glucose and facilitates insulin release by isolated pancreatic β-islet cells

Aqueous extract of Ocimum canum Sim, (Lamiaceae) is used by some Ghanaians to manage diabetes mellitus. In vivo modulation of levels of fasting blood glucose by 0. canum extract was evaluated in type-II diabetes mellitus using the C57BL/KsJ db/db genetically diabetic animal model, and its effects on glucose-stimulated insulin release in vitro were monitored using isolated rat pancreatic beta-islet cells. The results showed that fasting blood glucose levels and body weight decreased significantly (p < 0.05) in diabetic and non-diabetic C57BL/KsJ mice, which were administered aqueous extract of 0. canum. In vitro, the 0. canum extract significantly enhanced insulin release from isolated rat pancreatic beta-islet cells. Insulin release was found to be dependent on glucose concentration and increased with increasing O. canum concentration in the incubation medium up to an optimum extract concentration of 0.03 mg/ml. Release of the hormone decreased beyond this concentration of extract in the medium. Addition to the medium of Desmodium adscendens, a plant preparation used to manage inflammatory disorders, did not increase but rather inhibited insulin secretion by the pancreatic beta-islet cells. These results could explain the use of 0. canum in Ghanaian folk medicine to manage diabetes mellitus.     

Inhibition of lipid peroxidation by botanical extracts of Ocimum sanctum: in vivo and in vitro studies

Ocimum sanctum, the Indian holy basil, has significant ability to scavenge highly reactive free radicals. Shade dried leaf powder of the plant was extracted with water and alcohol, and then fractionated with different solvents. Both extracts and their fractions have in vitro anti-lipidperoxidative activity at very low concentrations. In vivo, hypercholesterolemia-induced erythrocyte lipid peroxidation activity was inhibited by aqueous extracts of Ocimum in a dose-dependent manner in male albino rabbits. Aqueous extract feeding also provided significant liver and aortic tissue protection from hypercholesterolemia-induced peroxidative damage.     

Scale-up micropropagation of sweet basil (Ocimum basilicum L.) in an airlift bioreactor and accumulation of rosmarinic acid

Nodal explants with lateral buds and leaf-derived suspension cultures of sweet basil, Ocimum basilicum L., were cultured in 5 l airlift bioreactors for three weeks, thereby increasing the fresh wt of suspension cultures 2.5-fold. Rosmarinic acid accumulated at 29 micromicrog g(-1) dry wt in the suspension culture but, for micropropagated plants, it reached 178 microg g(-1) dry wt.     

Essential‐Oil Variability in a Collection of Ocimum basilicum L. (Basil) Cultivars

Ocimum basilicum L. (Lamiaceae) is an aromatic plant of great tradition in the Mediterranean area. Its economic importance is growing up determining an expansion of cultivation. This paper evaluated the morphological traits, the chemical profiles, and antibacterial activity of 21 cultivars of basil belonging to ?Genovese?, ?Napoletano?, and ?Purple basil? types. The cultivars were characterized by different growth rate and morphological traits. The chemical composition of the oils analyzed by GC and GC/MS analysis, supported by the PCA analysis, underlined the strong influence of chemotype. It is noteworthy that estragole, never present in Genovese and purple basil types, occurred in Napoletano type. The high presence of eugenol, methyl eugenol, and linalool in the majority of cultivars, belonging both to Genovese and to Napoletano types was registered. Of great interest resulted the composition of the purple basil ?Opal?. All the samples tested exhibited similar antibiotic profiles with moderate antibacterial activity. The results enhanced the importance of determination of essential‐oil profile in the selection of cultivars characterized by diverse morphological traits and are useful for different purposes.     

Microbial interference ameliorates essential oil yield and diminishes root-knot infestation in sweet basil under field conditions

Despite the vast exploration of bioinoculants for disease resistance and crop yield enhancement, knowledge about their impact on quality and quantity of essential oil as well as induction of antioxidant is scarce, especially in medicinal and aromatic crops. In the present two-year field experimentation, a subset of Bacillus spp., namely Bacillus flexus, B. subtilis, B. megaterium and B. aryabhattai, was evaluated against the most devastating root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood infestation and essential oil yield enhancement in Ocimum basilicum var. CIM-Soumya (Sweet basil). The plants treated with B. subtilis showed significant (P < 0.05) enhancement in fresh biomass (42%), essential oil content (121%), nutrient uptake (83%) and reduced root-knot infestation (54%) as compared to untreated control. The defence afforded by bioinoculants was observed based on augmentation of the phenolic (97%), flavonoid (93%), free radical scavenging activity (34%) and total antioxidant (33%) in Bacillus-treated infected plants as compared to untreated infected plants. The higher concentration of essential oil constituents, namely linalool (54%) and methyl chavicol (33%), was also recorded in same treatment. An increase in essential oil yield was reflected by induction of antioxidant machinery. The present study for the first time delineates nematicidal potentials of B. flexus and B. aryabhattai. Altogether these findings suggest that exploitation of bioinoculants could be helpful for effective management of the root-knot nematode infestation along with higher qualitative and quantitative essential oil yield with augmented antioxidants in sweet basil.