Plant species belonging to the family Acanthaceae are globally known to possess various medicinal properties and have cultural and economic importance in both traditional medicine and horticulture. They are important to both animals and humans and are used as food or for ornamental purposes worldwide. Barleria is the third largest genus in the family Acanthaceae. A few of the highly important and reported species of Barleria include B. prionitis, B. cristata, B. grandiflora, and B. lupulina. The flowers, leaves, stems, roots, and seed extracts of plants belonging to this genus are rich in bioactive compounds and have exhibited significant medicinal potential for the treatment of various ailments and infections. Evidence derived from several studies has demonstrated the antioxidant, antibacterial, antifungal, anti-inflammatory, anticancer, antidiabetic, antiulcer, hepatoprotective, analgesic, antiamoebic, antihelminthic, antiarthritic, antihypertensive, antiviral properties and toxicity of extracts, in addition inhibition of acetylcholinesterase activity and biosynthesis of nanoparticles, of the plant and seed extracts of species belonging to Barleria. Studies have reported that bioactive compounds such as flavonoids, quinones, iridoids, phenylethanoid glycosides, the immunostimulant protein “Sankaranin”, and antibiotics isolated from Barleria species are resposnsible for the above biological activities. Traditionally, the genus Barleria has significant medicinal potential; however, there is a scarcity of information on various species that are yet to be evaluated. This review provides a comprehensive report on existing literature, concerning the phytochemistry and biological activities of the genus Barleria.

Several species belonging to the genus Tabernaemontana have been well researched and utilized for their wide-ranging biological activities. A few of the most prominent species include Tabernaemontana divaricata, Tabernaemontana catharinensis, Tabernaemontana crassa, and Tabernaemontana elegans. These species and many others within the genus often display pharmacological importance, which is habitually related to their chemical constituents. The secondary metabolites within the genus have demonstrated huge medicinal potential for the treatment of infections, pain, injuries, and various diseases. Regardless of the indispensable reports and properties displayed by Tabernaemontana spp., there remains a wide variety of plants that are yet to be considered or examined. Thus, an additional inclusive study on species within this genus is essential. The current review aimed to extensively analyze, collate, and describe an updated report of the current literature related to the major alkaloidal components and biological activities of species within the genus Tabernaemontana.

The bio-constituents of medicinal plants are greatly influenced by the environmental conditions and growing seasons. This study aimed to uncover the presence of different metabolites and to investigate the biological properties of the leaves of Mangifera indica during summer and winter seasons. The extract of M. indica leaves for summer and winter using different solvent extracts (hexane, chloroform, and methanol) showed the presence of phenols, flavonoids, tannins, terpenoids, alkaloids, phytosterol, saponins, steroids, and carbohydrates. Antibacterial activity of the methanolic leaf extracts for summer and winter were evaluated against the bacterial species Staphylococcus aureus (ATCC 43300) and Escherichia coli (ATCC 25922). For S. aureus (ATTC 43300), the summer crude extract displayed lower antibacterial activity than the control streptomycin, with zones of inhibition of 14.17 and 16.67 mm, respectively. Winter extracts had a zone of inhibition of 12 mm, while streptomycin had a 13.67 mm zone of inhibition. For E. coli (ATCC 25922), the summer crude extract displayed higher antibacterial activity than the control gentamycin, with zones of inhibition of 18.05 and 17.5 mm, respectively. The winter extracts had a zone of inhibition of 8.5 mm, while gentamycin had a 14.5 mm zone of inhibition. Antibacterial screening showed positive results for both seasons; however, summer extracts showed a more potent effect. The antioxidant screening was conducted using 2,2-diphenyl-1-picryl hydrazyl radical (DPPH) assay. Potent radical scavenging activity was exhibited for both summer and winter seasons with hexane and methanolic extracts for summer (IC₅₀ of 19.53 μg/mL and 12.71 μg/mL, respectively) and winter (22.32 μg/mL and 14.35 μg/mL, respectively) in comparison to the control ascorbic acid, which produced an IC₅₀ of 3.20 μg/mL. The summer leaf extracts had better radical scavenging IC₅₀ capacity than winter extracts. In conclusion, hexane and methanolic extracts had significant antioxidant activity, while methanolic extracts exhibited antibacterial activity. Further studies are required against more strains of bacteria and cancer cell lines to test for potency.

Genus Carissa represents several species that are reported to be of great phyto-medicinal and ethnopharmacological value. However, Carissa macrocarpa is relatively understudied. Furthermore, environmental conditions such as seasonal changes are known to affect the phytochemical composition of medicinal plants. Therefore, this study aimed to investigate the phytochemical composition and biological activity of the leaf extracts of C. macrocarpa in the summer and winter seasons. The phytochemical screening of C. macrocarpa leaves showed positive results for a variety of phytochemicals, such as alkaloids, tannins, phenols, naphthoquinones, flavonoids, saponins, steroids, proteins, carbohydrates, mucilage, gum and resin. The methanolic extract was evaluated for its antibacterial activity against Escherichia coli and Staphylococcus aureus using the agar well diffusion method. The winter leaf extract was distinguished for its potential antibacterial activity against both bacterial strains with inhibition zones (mm) of 8.17 ± 1.04 and 6.83 ± 0.58 at 10 mg/mL. The antioxidant activity of the leaf extracts was evaluated using the 2, 2′-diphenyl-1-picrylhydrazyl (DPPH) assay. The percentage scavenging activities of the different extracts were significantly greater than that of the control. Furthermore, at 15, 30, 60, 120 and 240 µg/mL, the percentage scavenging activities of the winter methanol leaf extract were 74.65, 78.31, 85.45, 90.02 and 95.68%, and those of the summer one were 71.66, 73.57, 84.05, 88.22 and 96.28%, respectively, indicating that the methanol leaf extract had greater percentage scavenging activity in winter than in summer. In winter, the IC₅₀ value of the methanol leaf extract (0.67 µg/mL) was lower than that of ascorbic acid (8.26 µg/mL). It is concluded that winter is the optimal season to harvest leaves of C. macrocarpa for medicinal use. To the best of our knowledge, this is the first report that relates the phytochemical composition and medicinal properties of C. macrocarpa to changes in seasons. The results obtained are promising, and this species should be further explored to decipher its pharmacological worth.