Secondary Metabolites

Abiotic stresses arising from climate change negates crop growth and yield, leading to food insecurity. Drought causes oxidative stress on plants, arising from excessive production of reactive oxygen species (ROS) due to inadequate CO 2 , which disrupts the photosynthetic machinery of plants. The use of conventional methods for the development of drought-tolerant crops is time-consuming, and the full adoption of modern biotechnology for crop enhancement is still regarded with prudence. Plant growth-promoting rhizobacteria (PGPR) could be used as an inexpensive and environmentally friendly approach for enhancing crop growth under environmental stress. The various direct and indirect mechanisms used for plant growth enhancement by PGPR were discussed. Synthesis of 1-aminocyclopropane−1-carboxylate (ACC) deaminase enhances plant nutrient uptake by breaking down plant ACC, thereby preventing ethylene accumulation, and enable plants to tolerate water stress. The exopolysaccharides produced also improves the ability of the soil to withhold water. PGPR enhances osmolyte production, which is effective in reducing the detrimental effects of ROS. Multifaceted PGPRs are potential candidates for biofertilizer production to lessen the detrimental effects of drought stress on crops cultivated in arid regions. This review proffered ways of augmenting their efficacy as bio-inoculants under field conditions and highlighted future prospects for sustainable agricultural productivity.

In this review, we synthesize the current knowledge of the ecology and impacts of Rhamnus cathartica L., a shrub from Europe and Asia that is a successful invader in North America. Physiological studies have uncovered traits including shade tolerance, rapid growth, high photosynthetic rates, a wide tolerance of moisture and drought, and an unusual phenology that may give R. cathartica an advantage in the environments it invades. Its high fecundity, bird-dispersed fruit, high germination rates, seedling success in disturbed conditions, and secondary metabolite production may also contribute to its ability to rapidly increase in abundance and impact ecosystems. R. cathartica impacts ecosystems through changes in soil N, elimination of the leaf litter layer, possible facilitation of earthworm invasions, unsubstantiated effects on native plants through allelopathy or competition, and effects on animals that may or may not be able to use it for food or habitat.

The influence of the morphology and differentiation of Aspergillus terreus hyphae on the formation of mevinolinic acid (lovastatin) and (+)-geodin was tested. Lovastatin titre was the highest (above 60 mg l−1) in the system with smaller pellets (diameter below 1.5 mm) and high biomass concentration (above 10 g l−1 in the idiophase). These biomass features were induced by the higher initial number of spores in the preculture (above 2 × 1010 l−1). At the initial number of spores below 2 × 109 l−1 (+)-geodin biosynthesis was the most efficient but it was rather connected with the elevated C/N ratio than with the pellet size. In order to quantify the hyphal differentiation in fungal pellets a special approach was used. The sectioning of the stained pellets together with the image analysis and calculation procedures were applied. The analysis of hyphal differentiation indicated that lovastatin formation was correlated with the fraction of the active, growing hyphae.

ÖZ Amaç: Coscinium fenestratum (Gaertn.) Colebr. (CF, Familya: Menispermaceae) Hindistan'da önemli bir odunsu bitkidir. Bitki çeşitli hastalıkların tedavisinde etkili olan çeşitli majör sekonder metabolitler içermektedir. Bu çalışmada, Coscinium fenestratum meyvelerinin antioksidan ve antihelmintik aktiviteleri değerlendirilmiştir. Gereç ve Yöntemler: Bu çalışmada, kurutulmuş meyvelerin sulu, metanollü ve sulu metanollü (1:1) ekstreleri hazırlanmış ve ekstrelerin alkaloit, fenolik, flavonoid içerikleri ile antioksidan (DPPH ve hidrojen peroksit süpürücü etki tayin yöntemi) ve antihelmintik aktiviteleri değerlendirilmiştir. ABSTRACT Objectives: Coscinium fenestratum (Gaertn.) Colebr. (CF, Family: Menispermaceae) is an important endangered woody climber in India. CF contains various major secondary metabolites for the treatment of various disease conditions. The present study aimed to establish the antioxidant and anthelmintic activity of Coscinium fenestratum fruit pulp. Materials and Methods: The dried fruit pulp was subjected to aqueous, methanol, and mixed aqueous and methanol (1:1) solvent extraction followed by phytochemical investigations, estimations of alkaloids, phenolics, flavonoids, antioxidant potentiality (DPPH and hydrogen peroxide scavenging methods), and anthelmintic activity tests were carried out. Results: Preliminary phytochemical screening of CF fruit extracts revealed the presence of alkaloids phenols, flavonoids, tannins, steroids, and resins, which are responsible for biologic properties. The combined aqueous and methanol extract resulted in significant anthelmintic and antioxidant properties in a dose-dependent manner. The DPPH free radical scavenging assay and H 2 O 2 assay exhibited IC 50 values of 42.38±0.012 μg/mL and 46.80±0.011 μg/mL, respectively. Thereafter, the anthelmintic activity test was carried out against Pheretima posthuma and Taenia solium with the extract at varying concentrations of 25, 50, 100 and 150 mg/mL and compared with standard albendazole (25 and 50 mg/mL) and saline (0.9%) as a control. All the extracts exhibited concentration-dependent paralytic effect, followed by death on the test organism, but significant activity was observed with the combined methanol and aqueous extract. Conclusion: The study was conducted in order to find possible isolated compounds as a biosources for future novel antioxidants in food and pharmaceutical formulations. Our findings indicate for the first time that the CF fruit pulp has therapeutic values with prominent antioxidant and anthelmintic properties.