Abstract
Pharmacognosy Research,2021,13,4,218-226.DOI:10.5530/pres.13.4.14Published:October 2021Type:Original ArticleAuthors:Bonface Mwamatope, David Tembo, Elizabeth Kampira, Cecilia Maliwichi-Nyirenda, and Victoria Ndolo Author(s) affiliations:Bonface Mwamatope1, David Tembo2,*, Elizabeth Kampira3, Cecilia Maliwichi-Nyirenda4, Victoria Ndolo5 1Biomedical Sciences Department, College of Medicine, University of Malawi, Blantyre, MALAWI. 2Physics and Biochemical Sciences Department, The Polytechnic, University of Malawi, Blantyre, MALAWI. 3Medical Laboratory Department, College of Medicine, University of Malawi. 4Research Support Centre, College of Medicine, University of Malawi, Blantyre, MALAWI. 5Department of Human Ecology, Faculty of Science, Chancellor College, University of Malawi, Blantyre, MALAWI. Abstract:Background: The study aimed at assessing total alkaloids content (TAC), total flavonoids content (TFC), total phenolic content (TPC), antioxidant activity (AA) and predominant individual phenolic compounds in methanol extracts of M. oleifera, S.singueana, M.azedarach leaves and stem barks of L. discolor collected during different seasons of the year. Materials and Methods: TPC, TFC and TAC were analyzed using the Folin Ciocalteau assay, aluminum chloride assay and bromocresol green assay, respectively. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) techniques were used to analyse AA. Phenolic compounds; Vanillic acid, (+)-catechin, quercetin, rutin, sinapic acid, 2,4-hydroxybenzoic acid and ferulic acid were analyzed using high performance liquid chromatography diode array detector (HPLC - DAD). Results: Barks of L. discolour exhibited high levels of TPC, TFC, TAC and AA during hot-dry season (summer) as compared to S. singueana, M. oleifera and M. azedarach leaves which showed significantly (p< 0.05) higher levels in hot-wet season (rainy). Levels of TPC, TFC and TAC were significantly (p< 0.05) influenced by seasonal variations and correlated with levels of AA. Profiles of all phenolic compounds analyzed were not similar in terms of chemical composition and concentration during different seasons. Sinapic acid and 2,4-hydroxybenzoic acid were predominant in S. singueana while sinapic acid and ferulic acid were predominant in M. oleifera. Vanillic acid and 2,4-hydroxybenzoic acid were predominant in L. discolor and M. azedarach respectively. Conclusion: The phytochemical constituents in medicinal plants are subject to seasonal variations which in turn influence the optimum season of harvesting. Keywords:Alkaloids, Antioxidant activity, Flavonoids, Medicinal plants, Phenolic compounds, Seasonal variationsView:PDF (984.49 KB)
Highlights
Background: The study aimed at assessing total alkaloids content (TAC), total flavonoids content (TFC), total phenolic content (TPC), antioxidant activity (AA) and predominant individual phenolic compounds in methanol extracts of M. oleifera, Senna singueana (Ss).singueana, M.azedarach leaves and stem barks of L. discolor collected during different seasons of the year
The analysis of total phenolic content in medicinal plants was carried out using Folin-Ciocalteu method because the assay is both simple and sensitive.[38]
High contents of total phenolic compounds during hot-wet season could be a result of high water and low temperature stress which can stimulate the accumulation of some phenolic compounds by hydrolysis of glycosides.[45]
Summary
There is increase in the use of plants as medicines world-wide, due to lack of access to conventional drugs, financial challenges and the ineffectiveness and side-effects of some conventional drugs.[1,2,3] Plant parts such as roots, leaves and barks are usually used as medicinal agents and sources of natural bioactive compounds that work for treatment of different ailments and as natural antioxidants.[4,5] These bioactive compounds such as flavonoids, anthraquinones, stilbenes, terpenes, alkaloids, tannins, saponins and phenolic compounds are synthesized in plants via different pathways, such as shikimic acid, salonic acid, mevalonic acid and non-mevalonate.[6,7] In many African countries including Malawi, some of these medicinal plants (e.g. S. singueana, L. discolor, M. oleifera and M. azedarach) are used for treatment of different diseases.[8,9,10,11,12,13]Senna singueana known as wild Cassia whose family is Fabaceae is used a lot in Africa for treating various ailments.[8,10] It has been claimed that this plant is effective in managing skin cancer,[8,14] diabetes, constipation, stomach pains, sexually transmitted infections, inflammation, fever and malaria.[15,16,17] Melia azedarach is a species of medicinal plant in Meliaceae family.[18,19] Some of reported pharmacological activities of this species include hepatoprotection, anti-fertility, antioxidant, anti-viral, anti-bacterial, wound healing, analgesic, insecticidal and anticancer.[18,20,21] Moringa oleifera belongs to a family of Moringaceae and is used to treat different ailments and prevent malnutrition.[9,11] The plant parts of M. oleifera possess some biological activities such as anti-cancer,[22] cardiac and circulatory stimulation, cholesterol lowering, antitumor, antioxidant, antibacterial and anti-fungal activity.[11,23] Lannea discolor belongs to the family of Anacardiaceae and this is used for treatment of different ailments.[10,12] Some of biological activities of this plant include anthelmintic, antiplasmodial, anti-cancer, nematicidal and antioxidant activity.[13,24]. The study aimed at assessing total alkaloids content (TAC), total flavonoids content (TFC), total phenolic content (TPC), antioxidant activity (AA) and predominant individual phenolic compounds in methanol extracts of M. oleifera, S.singueana, M.azedarach leaves and stem barks of L. discolor collected during different seasons of the year. Results: Barks of L. discolour exhibited high levels of TPC, TFC, TAC and AA during hot-dry season (summer) as compared to S. singueana, M. oleifera and M. azedarach leaves which showed significantly (p< 0.05) higher levels in hot-wet season (rainy). Levels of TPC, TFC and TAC were significantly (p< 0.05) influenced by seasonal variations and correlated with levels of AA.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
