Analysis of chemical compositions and larvicidal activity of nut extracts from Areca catechu Linn against Aedes (Diptera: Culicidae).

BACKGROUND: There is a growing need to use green alternative larvicidal control for Aedes larvae compared to chemical insecticides. Substantial reliance on chemical insecticides caused insecticide resistance in mosquito populations. Thus, research for alternate chemical compounds from natural products is necessary to control Aedes larvae. This study explores the analysis of chemical compositions from Areca catechu nut as a potential larvicide for Aedes (Diptera: Culicidae). METHODS: The Areca catechu nut collected from Ipoh, Perak, Malaysia was grounded into powder and used for Soxhlet extraction. The chemical analysis of the extracts and their structures were identified using the GCMS-QP2010 Ultra (Shimadzu) system. National Institute of Standards and Technology (NIST) Chemistry WebBook, Standard Reference Database 69 (https://webbook.nist.gov/chemistry/) and PubChem (https://pubchem.ncbi.nlm.nih.gov/), the two databases used to retrieve the synonyms, molecular formula, molecular weight, and 2-dimensional (2D) structure of chemical compounds. Next, following WHO procedures for larval bioassays, the extracts were used to asses larvicidal activity against early 4th instar larvae of Aedes aegypti and Aedes albopictus. RESULTS: The larvicidal activities were observed against early 4th stage larvae with different concentrations in the range from 200 mg/L to 1600 mg/L. The LC50 and LC95 of Aedes aegypti were 621 mg/L and 2264 mg/L respectively; whereas the LC50 and LC95 of Aedes albopictus were 636 mg/L and 2268 mg/L respectively. Mortality was not observed in the non-target organism test. The analysis using gas chromatography and mass spectrometer recovered several chemical compounds such as Arecaidine, Dodecanoic acid, Methyl tetradecanoate, Tetradecanoic acid , and n-Hexadecanoic acid bioactive components. These chemical constituents were used as additive formulations in pesticides, pest control, insect repellent, and insecticidal agents. CONCLUSIONS: Our study showed significant outcomes from the extract of Areca catechu nut and it deserves further investigation in relation to chemical components and larvicidal actions between different species of Aedes mosquitoes. Even though all these findings are fundamental, it may have some interesting potentials to be developed as natural bio-larvicidal products.

Licorice: A Potential Herb in Overcoming SARS-CoV-2 Infections.

The management of the global pandemic outbreak due to the coronavirus disease (COVID-19) has been challenging with no exact dedicated treatment nor established vaccines at the beginning of the pandemic. Nonetheless, the situation seems to be better controlled with the recent COVID-19 vaccines roll-out globally as active immunisation to prevent COVID-19. The extensive usage and trials done in recent outbreak in China has shown the effectiveness of traditional Chinese Medicines (TCM) in improving the wellbeing of COVID-19 patients. Therefore, COVID-19 Prevention and Treatment guidelines has listed a number of recommended concoctions meant for COVID-19 patients. Licorice, more commonly known as Gancao in Chinese Pinyin, is known as one of the most frequently used ingredients in TCM prescriptions for treatment of epidemic diseases. Interestingly, it is deemed as food ingredient as well, where it is normally used in Western cuisines' desserts and sweets. The surprising fact that licorice appeared in the top 10 main ingredients used in TCM prescriptions in COVID-19 has drawn great attention from researchers in revealing its biological potential in overcoming this disease. To date, there are no comprehensive review on licorice and its benefits when used in COVID-19. Thus, in this current review, the possible benefits, mechanism of actions, safety and limitations of licorice were explored in hope to provide a quick reference guide for its preclinical and clinical experimental set-up in this very critical moment of pandemic.