In vitro antioxidant properties, HIV-1 reverse transcriptase and acetylcholinesterase inhibitory effects of traditional herbal preparations sold in South Africa

The Immune Effects of an African Traditional Energy Tonic in In Vitro and In Vivo Models

Most of the African traditional medicines (ATM) are formulated as energy tonics to boost and maintain immune defences. In this study, we aimed to evaluate the immune effects of a traditional energy tonic using peripheral blood mononuclear cells (PBMCs), THP-1 monocytes, and bacteria infected rats. When tested in mitogen and peptidoglycan stimulated PBMCs, this energy tonic showed minimal cytotoxicity, while in acute toxicity studies in rats it did not exhibit any significant toxicity at doses up to 2000 mg/mL/kg. The energy tonic doses between 100 and 10 μg/mL were shown to stimulate secretion of cytokines and increase sIL-2R levels in PHA-treated PBMCs. Similar doses in PG-S. aureus-stimulated PBMCs significantly (p < 0.05) increased IL-1α, IL-2, and GM-CSF while causing a significant (p < 0.05) decrease in sIL-2R levels. NF-κβ transcriptional activity was increased in LPS stimulated THP-1 cells. In Sprague Dawley rats pretreated with the energy tonic and then infected with S. aureus, there were insignificant increases in cytokines and sIL-2R when compared to bacteria infected only and 5% Enrofloxacin treated rats. Posttreatment with energy tonic doses after infection with S. aureus did not enhance inflammatory cytokines significantly but changed the immune response profile and decreased corticosterone levels. This ATM showed promising immunomodulatory effects on isolated immune cells and modulated the immune response of rat models infected with S. aureus.

Phytochemical Profile and Antibacterial and Antioxidant Activities of Medicinal Plants Used by Aboriginal People of New South Wales, Australia

Aboriginal people of Australia possess a rich knowledge on the use of medicinal plants for the treatment of sores, wounds, and skin infections, ailments which impose a high global disease burden and require effective treatments. The antibacterial and antioxidant activities and phytochemical contents of extracts, obtained from eight medicinal plants used by Aboriginal people of New South Wales, Australia, for the treatment of skin related ailments, were assessed to add value to and provide an evidence-base for their traditional uses. Extracts of Acacia implexa, Acacia falcata, Cassytha glabella, Eucalyptus haemastoma, Smilax glyciphylla, Sterculia quadrifida, and Syncarpia glomulifera were evaluated. All extracts except that of S. quadrifida showed activity against sensitive and multidrug resistant strains of Staphylococcus aureus with minimum inhibitory concentration values ranging from 7.81 to 1000 μg/mL. The sap of E. haemastoma and bark of A. implexa possessed high total phenolic contents (TPC) and strong DPPH radical scavenging abilities. A positive correlation was observed between TPC and free radical scavenging ability. GC-MS analysis of the n-hexane extract of S. glomulifera identified known antimicrobial compounds. Together, these results support the traditional uses of the examined plants for the treatment of skin related ailments and infections by Aboriginal people of New South Wales, Australia.

Evaluation of the immunomodulatory effects of a South African commercial traditional immune booster in human peripheral blood mononuclear cells

BACKGROUND

With the burden of HIV and AIDS still very high, South Africa has seen an increase in commercial traditional medicines claiming to have immune-enhancing effects. Because of lack of regulation of the traditional medicine sector, these products have proliferated. This study aimed to evaluate the immunomodulatory effects of uMakhonya®, a commercial traditional immune booster, using various models of normal human peripheral blood mononuclear cells (PBMCs).

METHODS

Immunosuppressed, mitogen-, and peptidoglycan (PG)-stimulated PBMCs were treated with various doses of uMakhonya® and incubated for 24 h. The treated and control samples were analyzed for cytotoxicity, secretion of 12 different inflammatory cytokines, soluble interleukin-2 receptor (sIL-2R) levels, and nitric oxide (NO) secretion.

RESULTS

In cytotoxicity assays, uMakhonya® induced dose-dependent cytotoxic effects in all three models, with IC50 values of 512.08, 500, and 487.91 μg/mL for immunosuppressed, phytohaemagglutinin (PHA)-, and PG from Staphylococcus. aureus (PG-S. aureus)-stimulated PBMCs, respectively. UMakhonya® at 100 and 10 μg/mL induced a significant (p < 0.05) increase in the secretion of IL-1α, IL-1β, IL-6, IL-10, tumor necrosis factor alpha (TNF)-α, and granulocyte-macrophage colony-stimulating factor (GM-CSF) in cyclosporine-, immunosuppressed, and PHA-stimulated PBMCs. In the same samples, there was a significant increase (p < 0.05) in sIL-2R concentration, which correlated with an increase in the secretion of inflammatory cytokines. In PBMCs stimulated with PG-S. aureus, uMakhonya® at doses of 100 and 10 μg/mL significantly (p < 0.05) suppressed the secretion of inflammatory cytokines, especially IL-1β and TNF-α. PG-S. aureus-stimulated PBMCs also showed a significant decrease (p < 0.05) in sIL-2R concentration when compared to control samples. UMakhonya® insignificantly (p > 0.05) decreased NO levels in PBMCs after PG-S. aureus stimulation.

CONCLUSIONS

These results showed that uMakhonya® can induce both pro-inflammatory and anti-inflammatory effects depending on the initial stimuli applied to immune cells.

Antimutagenic and antioxidant effects of a South African traditional formulation used as an immune booster

Abstract The traditional medicines sector in South Africa is still largely unregulated despite legislation aimed at regulating the practice being in place. The HIV and AIDS epidemic has fuelled demand for traditional medicines, with many patients consulting traditional health practitioners who offer different treatments, including herbal immune boosters. This study investigated the mutagenic and antioxidant effects of the widely sold herbal immune booster, uMakhonya®. The Ames test was used for analysis of the genototoxic effects while the adenosine triphosphate (ATP) assay was used to evaluate cell cytotoxicity in peripheral blood mononuclear cells (PBMCs) and THP-1 monocytes. To evaluate the antioxidant effects the malondialdehyde (MDA) quantification, the nitric oxide and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) assays were used. UMakhonya® doses of up to 5000 μg/mL were not genotoxic in the Ames test. UMakhonya® was shown to induce dose-dependent cytotoxicity in both PBMCs and THP-1 cells with doses ranging from 500 μg/ mL to 1000 μg/mL, showing significant (p less than 0.05) toxicity. UMakhonya® was able to significantly (p less than 0.05) reduce nitrite radicals at 100 μg/mL while lower doses were not effective when compared to samples stimulated by lipopolysaccharide only. Non-cytotoxic doses of uMakhonya® showed significant (p less than 0.05) lipid peroxide scavenging ability in supernatants while this scavenging ability was considerably reduced intracellularly. In the DPPH assay, when both uMakhonya® and ascorbic acid were reconstituted in buffered saline, the traditional herbal remedy showed better radical scavenging abilities. Therefore further studies on the genotoxicity of uMakhonya®, when metabolically activated, and its antioxidant effects in in-vivo models are warranted

Enhanced HIV-1 Reverse Transcriptase Inhibitory and Antibacterial Properties in Callus of Catha edulis Forsk

Developing tissue culture systems for medicinal plants is important in that they may offer an alternative to protect wild populations. However, analysis of bioactivity for tissue culture developed plant tissues is required to offer support and allow acceptance in traditional medicine. The use of propagated callus could provide potential material for therapeutic purposes. This study was aimed at evaluating the anti-HIV and antibacterial properties of a three-month-old tissue culture-derived calli and leaves of cultivated mother plants of Catha edulis Forsk. The calli were derived from leaf explants using different plant growth regulators. The calli obtained from callus cultured on 9.8 μM indole-3-butyric acid plus 2.7 μM naphthalene acetic acid exhibited the highest HIV-1 reverse transcriptase inhibitory effects when compared with other treatments and the mother plants. Different extracts of callus exhibited high antibacterial activity (<1 mg/mL: minimum inhibitory concentration from 0.098 to 0.78 mg/mL) against both gram-positive and gram-negative bacteria. Leaf acetone extracts showed moderate activity (minimum inhibitory concentration of 0.78 mg/mL) against Staphylococcus aureus. The present study indicated that tissue culture-derived calli could be used as therapeutic agents for traditional medicine. The choice of treatment used in the tissue culture system and the age of the callus for production of biomass may significantly influence its therapeutic potential.

Phytochemical studies and antioxidant activity of two South African medicinal plants traditionally used for the management of opportunistic fungal infections in HIV/AIDS patients

Background

It has been observed that perturbations in the antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Hence, the exogenous supply of antioxidants, as natural compounds that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection. The aim of this study was therefore to analyse the phytochemical constituents and antioxidant potential of Gasteria bicolor Haw and Pittosporum viridiflorum Sims., two South African plants traditionally used for the management of opportunistic fungal infections (OFIs) in AIDS patients.

Methods

The in vitro antioxidant properties of the two plants were screened through DPPH (1,1-diphenyl-2-picrylhydrazyl), NO (nitric oxide), H₂O₂ (hydrogen peroxide) radical scavenging effects and reducing power assays. Phytochemical studies were done by spectrophotometric techniques.

Results

There were no significant differences in the flavonoid and proanthocyanidins contents between the leaves and bark extracts of Gasteria bicolor and Pittosporum viridiflorum respectively, while the total phenolic content of the bark extract of P. viridiflorum was significantly higher than that of G. bicolor leaf. The acetone extracts of both plants indicated strong antioxidant activities.

Conclusion

The results from this study indicate that the leaves and stem extracts of Gasteria bicolor and Pittosporum viridiflorum respectively possess antioxidant properties and could serve as free radical inhibitors, acting possibly as primary antioxidants. Since reactive oxygen species are thought to be associated with the pathogenesis of AIDS, and HIV-infected individuals often have impaired antioxidant defenses, the inhibitory effect of the extracts on free radicals may partially justify the traditional use of these plants in the management of OFIs in HIV patients in South Africa.

Anti-acetylcholinesterase and antioxidant activity of essential oils from Hedychium gardnerianum Sheppard ex Ker-Gawl

Acetylcholinesterase inhibition, antioxidant and cytotoxic activities of Hedychium gardnerianum leaf essential oils from S. Miguel Island were determined. All the oils inhibited acetylcholinesterase, with IC₅₀ values of approximately 1 mg/mL, showing no statistical differences between collection sites. Three oils presented mixed inhibition, whilst one was almost truly competitive. This activity can be attributed to the presence of sesquiterpenes, which constituted more than 60% of the composition of the oils. Regarding the antioxidant activity as measured by the DPPH method, all the oils presented activities similar to reference compounds, although with statistical differences between collection sites. Cytotoxicity measured using Artemia salina classified these oils as moderately toxic, with LC₅₀ values ranging from 300 to 500 µg/mL. These results indicate a possible application of these oils in aromatherapy as coadjuvants in the treatment of cognitive diseases such as Alzheimer, since they may contribute to increase acetylcholine in cholinergic neurons and simultaneously fight deleterious oxidations responsible by neurological degeneration.

In vitro testing of African traditional medicines for cytotoxic, immune modulatory and anti-HIV activities

African Traditional Medicines (ATMs) serve as a major source of primary healthcare for African people. The reasons for their use range from easy access, affordability, beliefs in traditional systems and long term safety. ATMs have been used to treat individuals infected with HIV and therefore need scientific validation; a view supported by Traditional Health Practitioners (THPs). This study aimed to evaluate the in vitro cytotoxicity, immune modulatory and anti-HIV activities of traditional multiple herbal preparations from local THPs. Ugambu, Ihashi, Product Nene, Product Blue, SPNa and SDKc ATM were supplied by local THPs. Changes in adenosine triphosphate (ATP) & glutathione (GSH) over 24 hours were measured using luminometry. Changes in 12 cytokines were assayed using an ELISA-based absorbance assay. Protective effects against HIV killing of MT-4 cells were tested using the XTT assay and antiviral activity was measured using an HIV-1 viral load assay. Cyclosporine and AZT were used as positive controls. Ugambu, Ihashi, Product Nene and SDKc induced a dose dependent toxicity on treated PBMCs by reducing ATP and GSH at high doses (p< 0.001). These medicinal preparations, along with SPNa, showed immunomodulatory activity by significantly (p< 0.001) changing the secretion of pro-inflammatory cytokines. Product Blue stimulated the levels of ATP and GSH in treated PBMCs at all doses however this product did not show any immunomodulatory activity on cytokine secretion when compared to control cells. Ugambu, Ihashi, Product Nene showed promising anti-HIV activity relative to AZT (p< 0.01). This study has shown that some of these traditional medicinal preparations have at least one or all the properties of immunostimulation, immunomodulation or antiretroviral effects. The mechanism of action of the shown activities should further be investigated.