Stilbenes: a journey from folklore to pharmaceutical innovation.

In modern times, medicine is predominantly based on evidence-based practices, whereas in ancient times, indigenous people relied on plant-based medicines with factual evidence documented in ancient books or folklore that demonstrated their effectiveness against specific infections. Plants and microbes account for 70% of drugs approved by the USFDA (U.S. Food and Drug Administration). Stilbenes, polyphenolic compounds synthesized by plants under stress conditions, have garnered significant attention for their therapeutic potential, bridging ancient wisdom with modern healthcare. Resveratrol, the most studied stilbene, initially discovered in grapes, red wine, peanuts, and blueberries, exhibits diverse pharmacological properties, including cardiovascular protection, antioxidant effects, anticancer activity, and neuroprotection. Traditional remedies, documented in ancient texts like the Ayurvedic Charak Samhita, foreshadowed the medicinal properties of stilbenes long before their modern scientific validation. Today, stilbenes are integral to the booming wellness and health supplement market, with resveratrol alone projected to reach a market value of 90 million US$ by 2025. However, challenges in stilbene production persist due to limited natural sources and costly extraction methods. Bioprospecting efforts reveal promising candidates for stilbene production, particularly endophytic fungi, which demonstrate high-yield capabilities and genetic modifiability. However, the identification of optimal strains and fermentation processes remains a critical consideration. The current review emphasizes the knowledge of the medicinal properties of Stilbenes (i.e., cardiovascular, antioxidant, anticancer, anti-inflammatory, etc.) isolated from plant and microbial sources, while also discussing strategies for their commercial production and future research directions. This also includes examples of novel stilbenes compounds reported from plant and endophytic fungi.

Plant growth-promoting endophyte Nigrospora oryzae mitigates abiotic stress in rice (Oryza sativa L.).

Climate change has severely impacted crop productivity. Nascent technologies, such as employing endophytic fungi to induce crop adaptogenic changes, are being explored. In this study, 62 isolates of fungi existing as endophytes were recovered from different parts of a drought-resistant rice variety and screened for salinity and drought tolerance. Nigrospora oryzae #2OSTUR9a exhibited in vitro antioxidant potential, indole acetic acid (351.01 ± 7.11 µg/mL), phosphate solubilisation (PI 1.115 ± 0.02), siderophore (72.57% ± 0.19%) and 1-aminocyclopropane-1-carboxylate deaminase production (305.36 ± 0.80 nmol α-ketobutyrate/mg/h). To the best of our knowledge, this is the first report on salinity and drought stress mitigation in rice plants by endophytic N. oryzae. In treated plants under salinity stress, the relative water, chlorophyll, phenolic and osmolyte content increased by 48.39%, 30.94%, 25.32% and 43.67%, respectively, compared with their respective controls. A similar trend was observed under drought stress, where the above parameters increased by 50.31%, 39.47%, 32.95% and 50.42%, respectively. Additionally, the antioxidant status of the treated plants was much higher because of the enhanced antioxidant enzymes and reduced lipid peroxidation. Our findings indicate the ability of N. oryzae to effectively mitigate the impact of stress, thereby enabling the rice plant to sustain stress conditions.

Promising drought and salinity tolerance features of Nigrospora species existing as endophytes in Oryza sativa.

In this study, we report the discovery of novel Nigrospora species isolated from the extensively cultivated PUSA 44 rice variety in Punjab, India. Out of the 120 isolates examined, 6.6% and 5% isolates exhibited tolerance to high salinity and drought stress. Isolates 6OSFR2e and 7OSFS3a exhibited the highest indole acetic acid and gibberellic acid production, with 268.32 ± 08.10 and 25.72 ± 0.04 µg/mL. Additionally, isolates 7OSFS3a, 6OSFR2e and 6OSFL4c had highest antioxidant potential with IC50 345.45 ± 11.66, 391.58 ± 10.66, and 474.529 ± 11.08 µg/mL. The isolates 6OSFR2e and 6OSFL4c also exhibited phosphate solubilisation with a PI of 1.06 ± 0.00 and 1.04 ± 0.02. The highest cellulase and laccase production with EI 1.24 ± 0.00 and 1.16 ± 0.00 was observed by isolates 6OSFR2e and 6OSFL4c. Promising results were observed in the case of ammonia production. The isolates belonged to the same phylum, Ascomycota and were identified as Nigrospora zimmermanii (6OSFR2e) and Nigrospora oryzae (7OSFS3a), and Nigrospora sphaerica (6OSFL4c) using morpho-taxonomic and molecular identification. The present study provides a critical insight into the characteristics of these Nigrospora species, which could be used to develop a bio-consortium for the rejuvenation of PUSA-44 cultivation. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03679-9.