@article {997, title = {Seasonal Variation of Phytochemicals in Four Selected Medicinal Plants}, journal = {Pharmacognosy Research}, volume = {13}, year = {2021}, month = {October 2021}, pages = {218-226}, type = {Original Article}, chapter = {218}, 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 variations}, doi = {10.5530/pres.13.4.14}, author = {Bonface Mwamatope and David Tembo and Elizabeth Kampira and Cecilia Maliwichi-Nyirenda and Victoria Ndolo} } @article {975, title = {A Phytochemical Analysis and In vivo Effects of an Herbal Aphrodisiac Newtonia hildebrandtii on Male Wistar Rat Reproductive System}, journal = {Pharmacognosy Research}, volume = {12}, year = {2020}, month = {August 2020}, pages = {243-249}, type = {Original Article}, chapter = {243}, abstract = {

Background: The study was aimed at screening phytochemicals and evaluating the effects of aqueous and 50\% (v/v) methanol stem bark extracts of Newtonia hildebrandtii on male rat reproductive system. Materials and Methods: Thirty male Wistar rats were divided into five groups and were given different treatments of N. hildebrandtii extracts at 200 and 400 mg/kg body weight. After 8 weeks, body and right testis weight, sperm concentration, hormonal levels, and histological structure of the testis were evaluated. Calorimetric method was used for quantitative analysis of phenolic compounds, whereas gas chromatography{\textendash}mass spectrometry (GC-MS) was used for fingerprinting of chemical compounds. Results: Testosterone, luteinizing hormone, estradiol, and follicle-stimulating hormone levels were significantly increased, whereas prolactin levels were significantly decreased in the treated groups compared to the control. Sperm parameters were significantly increased compared to the control. Treated animals showed significant increases in body weight, seminiferous tubule diameter, and germinal epithelial height with the testes showing all the stages of spermatogenesis. Phytochemical screening of the methanolic extracts revealed the presence of alkaloids, carbohydrates, reducing sugars, steroids, anthraquinones, flavonoids, phenols, and saponins. GC-MS analysis revealed the presence of dimethylsilanediol; (R, R)-2,3-butanediol; hexamethylcyclotrisiloxane; succinimide; 1H-1,2,3-triazole-4-carboxylic acid, 1-(4-amino-1,2,5-oxadiazol-3-yl)-5-ethyl-, ethyl ester; l-(+)-ascorbic acid 2,6-dihexadecanoate; cis-13,16 docasadienoic acid, methyl ester; 9-octadecenoic acid (Z)-, 2-hydroxy-1-(hydroxymethyl) ethyl ester; and 2-chloro-benzoic acid N{\textquoteright}-[2-(3-oxo-3,4-dihydro-2H-benzo[1,4]thiazin-2-yl)-acetyl]-hydrazide. Conclusion: N. hildebrandtii appears to possess androgenic and anabolic effects. The aforementioned phytochemicals seem to be responsible for its aphrodisiac effects. This study supports the ethno-aphrodisiac claims that have been made against it.

}, keywords = {Antioxidants, DPPH, Estradiol, Seminiferous tubule, Sperm concentration, Spermatogenesis, Testosterone, Total flavonoids, Total phenols}, doi = {10.4103/pr.pr_112_19}, author = {Thomson Msiska and Anthony Mwakikunga and David Tembo and Fanuel Lampiao} }