The role of priming and memory in rice environmental stress adaptation: Current knowledge and perspectives.

Plant responses to abiotic stresses are dynamic, following the unpredictable changes of physical environmental parameters such as temperature, water and nutrients. Physiological and phenotypical responses to stress are intercalated by periods of recovery. An earlier stress can be remembered as 'stress memory' to mount a response within a generation or transgenerationally. The 'stress priming' phenomenon allows plants to respond quickly and more robustly to stressors to increase survival, and therefore has significant implications for agriculture. Although evidence for stress memory in various plant species is accumulating, understanding of the mechanisms implicated, especially for crops of agricultural interest, is in its infancy. Rice is a major food crop which is susceptible to abiotic stresses causing constraints on its cultivation and yield globally. Advancing the understanding of the stress response network will thus have a significant impact on rice sustainable production and global food security in the face of climate change. Therefore, this review highlights the effects of priming on rice abiotic stress tolerance and focuses on specific aspects of stress memory, its perpetuation and its regulation at epigenetic, transcriptional, metabolic as well as physiological levels. The open questions and future directions in this exciting research field are also laid out.

Bioactive fractions from Allium humile alleviate the risk of high fat diet induced atherosclerosis in albino Wistar rats by inhibiting protein kinase C.

Atherosclerosis is a global concern that worsens with age, and plants that are effective medicinal herbs can give a viable alternative. PKC is a key factor in cardiovascular and other disorders; targeting it can reduce the risk of these diseases. We evaluated Allium humile for PKC inhibition and therapeutic efficacy against atherosclerosis. Soxhlet extraction was done to obtain extracts (hexane, ethyl acetate, methanol, ethanol and aqueous) and then tested for DPPH radical scavenging and PKC inhibitory activity. The methanolic extract was more active than the other extracts, so it was subjected to column chromatography, and seventeen fractions were obtained. Only 11, 12, and 15 showed good activity against PKC. Wistar rats were divided into six groups and each group received high fat diet for 30 days. Then the three potent fractions (10 mg/kg) were administered for 15 days along with high fat diet. Fraction II had the highest effectiveness (P < 0.0001) in decreasing lipid levels, lipid peroxidation, reducing IL-6 and TNF-α expression, and raising nitric oxide. This also demonstrated a decrease in PKC activity, as well as a decrease in the formation of the lipoidal layer in the aorta wall and rupture of the intima and media as validated by histological analysis. The two compounds, phytol acetate and cyanidin 3-(6″-o-malonyllaminaribioside) were characterised in fraction II by NMR and HRMS and cyanidin 3-(6″-o-malonyllaminaribioside) inhibited PKC more efficiently. Thus, Allium humile has strong anti-atherogenic activity as well as the ability to inhibit PKC both in vitro and in vivo.

Studies on the ameliorative potential of Rheum webbianum rhizome extracts on 1,2-dimethylhydrazine (DMH) induced colorectal cancer and associated hepatic and haematological abnormalities in swiss albino rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheum webbianum Royle (RW) holds significant ethnopharmacological importance owing to its 5000-year history of cultivation for medicinal and culinary purposes. Demonstrating therapeutic advantages in traditional and contemporary medical practices, RW exhibits key pharmacological effects including anticancer activity, gastrointestinal control, anti-inflammatory properties, and suppression of fibrosis. Despite its recognized vast bioactivities in ethnopharmacology, its efficacy against the colorectal cancer (CRC) remains incompletely understood. AIM OF THE STUDY: This study for the first time aims to investigate the chemo-preventive capabilities of various extracts derived from RW rhizomes against CRC development. MATERIALS AND METHODS: Four types of RW extracts were prepared by using different solvents viz: Hexane, Ethy-acetate, Ethanol and Methanol. All the four extracts were evaluated for cytotoxicity on HCT-116 human CRC cells. Promising extracts were further investigated in-vivo at varying doses using 1,2-dimethylhydrazine (DMH) induced rat CRC model to assess the anti-oxidant and anticancer properties as well as their effects on the associated hepatic deterioration and hematological alterations. RESULTS: Cell viability: In-vitro assessments demonstrated a dose and time-dependent reduction in HCT-116 cell viability following treatment with methanolic and ethanolic extracts of RW, reducing viability by up to 85% and 90%, respectively, at 200 µg/ml. HISTOPATHOLOGY: Histopathological analyses revealed significant improvements in colon tissue morphology in RW extract-treated groups compared to DMH-only treated animals. RW-treated groups showed reduced structural abnormalities, congestion, inflammatory cell infiltration, crypt abscess formation, and dysplasia. In contrast, the DMH-only group exhibited irregular glandular structure, mucosal destruction, extensive inflammatory cell infiltration, crypt abscess formation, and dysplasia. These results highlight the potential of RW methanolic and ethanolic extracts in mitigating colon cancer-related histopathological alterations. Haematological, and hepatic parameters: In the DMH-induced colorectal cancer rat model, significant hematological imbalances were evident, including a 49.13% decrease in erythrocytes, 32.18% in hemoglobin, and 26.79% in hematocrit, along with a 79.62% increase in white blood cells and 68.96% rise in platelets. Administration of RW rhizome extracts effectively restored these hematological parameters to levels comparable to those in the control group. Furthermore, RW treatment significantly reduced serum ALT and AST levels, which had increased by 36.78% and 33.12%, respectively, due to DMH exposure. RW intervention also mitigated the onset of atherosclerosis, evidenced by notable reductions in serum total cholesterol and triglyceride levels. Comparative analysis indicated that RW-treated DMH groups effectively restored lipid profiles, contrasting with the DMH-only group which exhibited markers indicative of colon cancer. Oxidative stress: The DMH-treated group showed a significant increase in MDA levels by 195.59%, indicative of heightened free radical production, coupled with decreased levels of SOD (33%), CAT (48%), GSH (58%), and GR activity (49%), signifying oxidative stress. Treatment with RW extracts in DMH-treated rats markedly reduced MDA levels and enhanced SOD, CAT, GSH, and GR activities. These results underscore the antioxidant efficacy of RW extracts. CONCLUSION: This study underscores the significant potential of RW rhizome extracts in inhibiting colorectal cancer development. Further investigations are warranted to identify the active constituents responsible for these promising outcomes, positioning RW as a natural and potential agent in combating colon cancer.

Bioactive potential of Lagotis cashmeriana: a study on morphology, phytochemicals, and antioxidant activity.

The present study aimed to investigate the morphological features, phytochemicals, phenolic content, and antioxidant activity in different parts of Lagotis cashmeriana. The morphological features depicted that the plant is 7.9 ± 1.699 cm tall with flowers arranged into an inflorescence. The length of inflorescence was 2.597 ± 0.796 cm. Basal leaves were measuring 2.99 ± 0.58 cm. Besides, the number of basal leaves and inflorescence ranged from 4-9 and 0-4 respectively. Methanolic extract of leaves displayed the highest phenolic content (169.5 µg/mL of GAE), followed by inflorescences (157 µg/mL of GAE). Among aqueous extracts, leaves displayed the highest phenolic content (88.38 µg/mL of GAE), followed by inflorescences (76.95 µg/mL of GAE). The results of antioxidant study revealed that the methanolic extracts of leaves possessed the highest antioxidant potential (180.76 µg/mL of AAE). Interestingly, for each extract, there was a positive correlation between the phenolic content and the antioxidant activity.