The aim of this study was to determine the antioxidant activity of the extractable and non-extractable phenolics of Terminalia. Sericea Burch. Ex DC. Free, ester bound, ether or glycoside bound and insoluble phenolics were extracted from the fruit, leaves, stem, and root samples. Follin Ciocalteu was used to estimate the phenolic content while DPPH (2,2-diphenyl-1-picrylhydrazyl) assay was used to determine the antioxidant activity. The data obtained were subjected to multivariate analysis for relationships. The result indicated that the highest average total phenolic contents and antioxidant activities were found in the free (14.8 mgGAE/g; IC50 6.8 μg/mL) and ester bound (15.1 mgGAE/g; IC50 6.4 μg/mL) extractable phenolics. There was a strong negative correlation between TPC and DPPH (r = −0.828). Agglomerative hierarchical clustering revealed three clusters. Cluster one contained the insoluble and glycoside phenolics while cluster 2 contained only free phenolic acid of the root. The third cluster was predominantly free and ester bound phenolic extracts. The principal component analysis score plot indicated two major clusters with factor 1 (F1) explaining 61% of the variation. The nuclear magnetic resonance spectroscopy spectra indicated that gallic acid and resveratrol are the major phenolic compounds present in the root. This study has demonstrated that extractable phenolics contributed more to the antioxidant activities compared to the non-extractables.

Background: The Vhembe region of the Limpopo province has a rich tradition of medicinal plants use. Traditionally, boiled roots of Ziziphus mucronata are used in the treatment of boils, general swelling and other skin infections. A combination of leaf paste and root infusion treats measles, dysentery, chest complains, and gland swelling. Pterocarpus angolensis is famous for the treatment of menorrhagia, infertility in women, wounds and pain management. The purpose of the present study was to compare the cytotoxicity, anti-inflammatory potential and anti-microbial activities of Ziziphus mucronata and Pterocarpus angolensis from the Vhembe region. Method: U937, MeWo, Vero and RAW 264.7 cells were treated to various concentrations (50, 100, or 125 or 250 μg/ml depending on assays) of Ziziphus mucronata and Pterocarpus angolensis. Cytotoxicity assay was done using MTT; Antiinflammatory activity was assessed using NO production; Anti-bacterial activity was done using the Micro-Broth dilution method and Anti-mycobacteria activity was determined using the Alamar Blue Method while RT activity was measured by ELISA. Results: Cytotoxicity results showed that Pterocarpus was more toxic than Ziziphus as observed in the Vero and MeWo cells; however both displayed toxicity towards a Human cancer cell line. Both extracts did not inhibit nitrate production but induced significant increase in macrophage activation. The plant extracts have shown anti-tuberculosis activity at concentrations >500 μg/ml and there was moderation inhibition of HIV replication. Conclusions: The results obtained indicated that the extracts have pro-inflammatory properties, and the observed toxicity on malignant cell lines must be investigated further for promising anti-cancer drug therapy.

Momordica balsamina (M. balsamina) is a medicinal herb comprising health-promoting secondary metabolites. This study was aimed to profile bioactive compounds in the methanolic extract of M. balsamina leaves using molecular spectroscopic (UV-Vis and FTIR) and hyphenated chromatographic (UHPLC-qTOF-MS) techniques and evaluate the biological (in vitro anti-inflammatory and cytotoxicity) activities of the extract. The preliminary phytochemical screening tests revealed the presence of cardiac glycosides, flavonoids, saponins, tannins, and terpenoids. The UV-Vis profile revealed various absorption bands ranging from 200 to 750 nm, indicating the presence of flavonoids, phenolic compounds, tannins, terpenoids, carotenoids, chlorophyll, and alkaloids. FTIR spectra confirmed the presence of alkaloids, flavonoids, terpenes, anthraquinones, and phenolic compounds. A high-resolution and accurate mass spectrometer (LC-QTOF-MS model LC-MS-9030 instrument) was used, and the results confirmed the presence of flavonoid aglycones, such as quercetin, isorhamnetin, and kaempferol, as well as pseudolaroside A and dicaffeoylquinic and feruloyl isocitric acids. To the best of our knowledge, this is the first report of pseudolaroside A dimer and feruloyl isocitric acid in M. balsamina leaves. In vitro cytotoxicity assay showed that the extract was nontoxic against human colorectal adenocarcinoma (HT29 and Caco2), Vero, and RAW 264.7 cells. However, the extract showed anti-inflammatory activity on RAW 264.7 cells. The study confirmed that M. balsamina leaves contain nontoxic secondary metabolites that may play a pivotal role in human health as anti-inflammatory agents.

Malaria parasites are increasingly becoming resistant to currently used antimalarial therapies, therefore there is an urgent need to expand the arsenal of alternative antimalarial drugs. In addition, it is also important to identify novel antimalarial drug targets. In the current study, extracts of two plants, Pterocarpus angolensis and Ziziphus mucronata were obtained and their antimalarial functions were investigated. Furthermore, we explored the capability of the extracts to inhibit Plasmodium falciparum heat shock protein 70 (Hsp70) function. Heat shock protein 70 (Hsp70) are molecular chaperones whose function is to facilitate protein folding. Plasmodium falciparum the main agent of malaria, expresses two cytosol-localized Hsp70s: PfHsp70-1 and PfHsp70-z. The PfHsp70-z has been reported to be essential for parasite survival, while inhibition of PfHsp70-1 function leads to parasite death. Hence both PfHsp70-1 and PfHsp70-z are potential antimalarial drug targets. Extracts of P. angolensis and Z. mucronata inhibited the basal ATPase and chaperone functions of the two parasite Hsp70s. Furthermore, fractions of P. angolensis and Z. mucronata inhibited P. falciparum 3D7 parasite growth in vitro. The extracts obtained in the current study exhibited antiplasmodial activity as they killed P. falciparum parasites maintained in vitro. In addition, the findings further suggest that some of the compounds in P. angolensis and Z. mucronata may target parasite Hsp70 function.

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