Antioxidant and genotoxic properties of South African herbal extracts

Traditional Medicinal Plants Conferring Protection Against Ovalbumin-Induced Asthma in Experimental Animals: A Review

Asthma is a chronic inflammatory disease of the respiratory tract in which the numerous immune cells, including eosinophils, neutrophils, macrophages, T-lymphocytes, mast cells and epithelial lining play key roles. The numerous anti-asthmatic drugs are available in modern medicine to treat asthma, but they have several disadvantages, including side effects and the cost variations, which compromise treatment compliance. The literature review reveals that traditional herbal medicines have good potential as alternative treatment and management for asthma. However, communities hesitated to use the traditional herbal medicines due to lack of established mechanism of action about their anti-asthmatic potential. The present review aimed to summarise the information stated in the literature about the potential effect of traditional medicinal plants (TMPs) conferring protection against ovalbumin (OVA)-induced asthma model. The literature search was conducted in database like PubMed, Scopus, Google Scholar and ScienceDirect. After screening through the literature from 2011 to date, a total of 27 medicinal plants and two polyherbal extracts have been reported to be used as traditional herbal medicines and also utilised to be tested against OVA-induced asthma, were included. We found them to be an important alternative source of treatment for asthma, since some have comparable efficacies with drugs commonly used in the modern system against asthma. All the reported medicinal plants confirmed their traditional use against asthma or its related inflammation. The present review provides faith in traditional information and also offers new insight into the potential of natural products against asthma.

Microbiological quality and genotoxicity of domestic water sources: A combined approach using Micro Biological Survey method and mutagenesis assay (micronucleus test) in root tips of Vicia faba in the West region of Cameroon

At least 2.1 billion people around the world use contaminated drinking water, causing 485,000 diarrheal deaths each year, mostly among children under 5 years old. A study conducted 10 years ago in Bafoussam (West Cameroon) recorded concentrations of bacteria among surface and groundwater. High levels of bicarbonates, phosphates, chlorides and suspended matters were also found. The aim of this study was to assess the microbiological and chemical qualities of domestic water sources in 5 localities of the West region of Cameroon. Water samples from 22 water sources (wells, springs, water drilling and river) were aseptically collected in plastic bottles and transferred in 50 ml sterile tubes. For chlorinated water sources, 1 ml of Thiosulfate was added to the water sample; immediately placed in an ice box and transported to the laboratory for analysis. Water temperature and pH were measured on site. The microbiological quality of water was determined by testing Total Coliforms (TC) using the Micro Biological Survey method. 1 ml of each water sample was inoculated in the MBS vial initially rehydrated with 10 ml of sterile distilled water. The initial color of the vials is red. Color changes were monitored at three different time intervals (12h, 19h and 24h), corresponding to three levels of contamination. The chemical quality of water was assessed using micronucleus (MN) test in selected Vicia faba seeds secondary root tips permanently mounted in Dibutylphthalate Polystyrene Xylene mountant for histology after 72 hours of direct exposition in water samples and in dark. The mitotic indices and MN frequencies were evaluated in 10 root tips per site analysing 5000 cells per tip. Statistical analyses were done using Stata IC/15.0 software. The Student t-test was used for mean comparison and the significance level was set at 1%. The majority of samples were collected from wells (63.6%). The mean water pH ranged from 5.5 to 8.3 and the temperature varied from 23 to 26°C. A very high concentration of TC [>10³ CFU/ml] was found in 8 (36.4%) samples. 10 (45.5%) and 2 (9.1%) samples turned yellow at 19 and 24 hours respectively after incubation corresponding to TC concentration of [10<x<10³ CFU/ml] and [1<x< 10 CFU/ml]. The MN frequency was higher (P ≤ 0.01) compared to the negative control in 9 (40.9%) water samples indicating significant genotoxic effects of these water sources. This study highlighted the poor quality of domestic water sources in West region of Cameroon and the need to conduct regular monitoring of drinking water sources. Community capacity building on water treatment methods, including good wastes management should be implemented to help improve water quality.

Study of Antioxidant, Antiproliferative and DNA Damage Protecting Activities of Cinnamomum cassia Extracts Obtained by Sequential Extraction

BACKGROUND

Cinnamomum cassia (C. cassia) is an evergreen tree in China and Southern and Eastern Asia. In traditional medicine, cinnamon is widely used due to its many bioactivity effects.

OBJECTIVE

The present novel study aims to evaluate and make a comparison of antioxidant and antiproliferative activities of different extractions of C. cassia bark using seven solvents having different polarities. Solvents polarity gradients start with the solvent of lower polarity, n-hexane, and end with water as the highest polar solvent. Among the extracts, acetone extract contains the highest phenolic and flavonoid contents; therefore, it is assessed for the ability to protect DNA from damage.

METHODS

The extracts are evaluated for total phenolic, flavonoid contents and antioxidant activities, using FRAP, DPPH, superoxide, and hydroxyl and nitric oxide radicals scavenging assays. DNA damage protecting activity of the acetone extract is studied with the comet assay. Each of the extracts is studied for its antiproliferative effect against, MCF-7, MDA-MB-231(breast cancer), and HT29 (colon cancer), using MTT assay.

RESULTS

The acetone extract exhibited the highest FRAP value, phenolic and flavonoids contents when compared to the other extracts and could protect 45% mouse fibroblast cell line (3T3-L1) from DNA damage at 30 μg/ml. The lowest IC50 value in DPPH, superoxide, and hydroxyl radicals scavenging was noticed in the ethyl acetate extract. IC50 value obtained for the hexane extract was the lowest compared to the other extracts in scavenging nitric oxide radicals. The hexane extract showed the highest antiproliferative effect against cancer cells followed by the chloroform extract. The ethyl acetate extract inhibited the proliferation of only MCF-7 by IC₅₀ of 100 μg/ml, while the other extracts exhibited no IC₅₀ in all the cancer cells.

CONCLUSION

C. cassia showed promising antioxidant and anticancer activities with significant DNA damage protecting effect.

Occurrence and Risk of Metal(loid)s in Thelesperma megapotamicum Tea Plant

This study reports on the harvesting, ingestion, and contamination of American Indian tea Thelesperma megapotamicum grown on the Navajo Reservation in New Mexico. Uranium (U) and co-metal(loid)s (As, Cd, Cs, Mo, Pb, Se, Th, and V) have contaminated local soil and plants. Tea plants were gathered for analysis near U mining impacted areas. The study collected samples of wild tea plants (n = 14), roots (n = 14), and soil (n = 12) that were analyzed with inductively coupled plasma mass spectrometry. Tea harvesting activities, behavior, and ingestion information were collected via questionnaires. Harvesting took place in community fields and near roadways. Results indicate edible foliage concentration levels for Cd exceeded the World Health Organization (WHO) raw medicinal plant permissible level guidelines. Tea samples collected near high traffic areas had significantly greater Cd and Mo concentrations than those collected near low traffic areas (p < 0.001). Tea sample metal(loid) concentration levels ranged from 0.019-7.916 mg/kg. When compared to established food guidelines including the WHO provisional tolerable weekly intake (PTWI), reference dietary intake, recommended dietary allowance, and the tolerable upper limit (UL), Cd exceeded the WHO guidelines but none exceeded the PTWI nor the UL. These findings warrant improved standardization and establishment of universal guidelines for metal(loid) intake in food.

In-vitro cytotoxicity of various Siphonochilus aethiopicus (Schweinf.) B.L. Burtt extracts in combination with selected tableting excipients

OBJECTIVES

To investigate the cytotoxic potential of S. aethiopicus extracts in combination with chitosan and Pharmacel^® 101, on two cell lines.

METHODS

Extracts were chemically characterised utilising UPLC-Q-TOF/MS, followed by determination of cell viability and membrane integrity.

KEY FINDINGS

Ethanol (EtOH) and diethyl ether (DiEt) extracts contained significant quantities of all chosen biomarker molecules; however, only two were scarcely quantifiable in aqueous extracts. Aqueous extracts did not induce any cytotoxic effects, whereas EtOH and DiEt extracts caused concentration-dependent decreases in cell viability and membrane integrity loss in both cell lines. Ensuing exposure to EtOH extracts at 50, 100 and 150 μg/ml, HepG2 cells were considered 15.5%, 12.5% and 32.8% apoptotic, whereas DiEt extracts caused 4.5%, 13.5% and 33.9% apoptotic cells. Exposure to EtOH and DiEt extracts at 50 μg/ml ensued in 20.2% and 21.3% apoptosis in Caco-2 cells; 100 μg/ml induced apoptosis in 19.9% and 10.3% of Caco-2 cells; whereas exposure to 150 μg/ml EtOH extracts caused 12.6% apoptosis compared to 11.7% induced by the DiEt extract.

CONCLUSIONS

None of the excipients caused any significantly altered cellular effects, indicating little chance for physicochemical interactions. Aqueous extracts did not possess any cytotoxic properties. However, it is clear that organic extracts caused apoptotic and necrotic cell death.

Ethnobotanical Survey of Medicinal Plants Used to Treat Mental Illnesses in the Berea, Leribe, and Maseru Districts of Lesotho

Mental illnesses (MIs) such as anxiety, epilepsy, major depression, schizophrenia, sleep disorder, and pain influence the quality of life severely. According to the World Health Organization Atlas for Mental Health (2014), the formal health sector in Lesotho has only 13.7 mental health workers per 100 000 of the population, which breaks down to 0.1 psychiatrist and other medical doctors, 0.3 psychologists, 4.7 nurses, and 5.2 social workers. Traditional health practitioners (THPs) have always played a significant role in the prevention and treatment of MIs, via utilization of Lesotho’s vast diversity of plants. This investigation aims to determine which medicinal plants are used for the treatment of MIs in the Berea, Leribe, and Maseru districts of Lesotho. A combination of unstructured and semistructured one-on-one interviews were conducted with 27 THPs. They were interviewed about the status of MIs in Lesotho, diagnostic methods, medicinal plants used, and preparation and administration of the herbal remedies in the treatment of MIs. A total of 43 different plant species (indigenous and exotic) were indicated by the THPs as commonly used to treat neurological disorders. With the exception of one unidentified plant, the plants represented 26 families and 42 genera. The most common families are the Asteraceae (9 species), Fabaceae (5 species), and Rosaceae (3 species). The most cited plant species were Morella serrata (Myricaceae) (26%), followed by Xysmalobium undulatum (Asclepiadaceae) (22%), and Afroaster hispidus (Asteraceae) (15%). This survey provides, for the first time, a database of Lesotho’s medicinal plants that are used to treat MIs.

African Herbal Remedies with Antioxidant Activity: A Potential Resource Base for Wound Treatment

The use of traditional herbal remedies as alternative medicine plays an important role in Africa since it forms part of primary health care for treatment of various medical conditions, including wounds. Although physiological levels of free radicals are essential to the healing process, they are known to partly contribute to wound chronicity when in excess. Consequently, antioxidant therapy has been shown to facilitate healing of such wounds. Also, a growing body of evidence suggests that, at least, part of the therapeutic value of herbals may be explained by their antioxidant activity. This paper reviews African herbal remedies with antioxidant activity with the aim of indicating potential resources for wound treatment. Firstly, herbals with identified antioxidant compounds and, secondly, herbals with proven antioxidant activity, but where the compound(s) responsible for the activity has not yet been identified, are listed. In the latter case it has been attempted to ascribe the activity to a compound known to be present in the plant family and/or species, where related activity has previously been documented for another genus of the species. Also, the tests employed to assess antioxidant activity and the potential caveats thereof during assessment are briefly commented on.

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.

Warburgia: a comprehensive review of the botany, traditional uses and phytochemistry

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Warburgia (Canellaceae) is represented by several medicinal trees found exclusively on the African continent. Traditionally, extracts and products produced from Warburgia species are regarded as important natural African antibiotics and have been used extensively as part of traditional healing practices for the treatment of fungal, bacterial and protozoal infections in both humans and animals. We here aim to collate and review the fragmented information on the ethnobotany, phytochemistry and biological activities of ethnomedicinally important Warburgia species and present recommendations for future research.

MATERIALS AND METHODS

Peer-reviewed articles using "Warburgia" as search term ("all fields") were retrieved from Scopus, ScienceDirect, SciFinder and Google Scholar with no specific time frame set for the search. In addition, various books were consulted that contained botanical and ethnopharmacological information.

RESULTS

The ethnopharmacology, phytochemistry and biological activity of Warburgia are reviewed. Most of the biological activities are attributed to the drimane sesquiterpenoids, including polygodial, warburganal, muzigadial, mukaadial and ugandensial, flavonoids and miscellaneous compounds present in the various species. In addition to anti-infective properties, Warburgia extracts are also used to treat a wide range of ailments, including stomach aches, fever and headaches, which may also be a manifestation of infections. The need to record anecdotal evidence is emphasised and conservation efforts are highlighted to contribute to the protection and preservation of one of Africa's most coveted botanical resources.

Single and combined effects of deoxynivalenol mycotoxin and a microbial feed additive on lymphocyte DNA damage and oxidative stress in broiler chickens

The immune and intestinal epithelial cells are particularly sensitive to the toxic effects of deoxynivalenol (DON). The aim of this experiment was to study the effects of DON and/or a microbial feed additive on the DNA damage of blood lymphocytes and on the level of thiobarbituric acid reactive substance (TBARS) as an indicator of lipid peroxidation and oxidative stress in broilers. A total of forty 1-d-old broiler chicks were randomly assigned to 1 of 4 dietary treatments (10 birds per group) for 5 wk. The dietary treatments were 1) basal diet; 2) basal diet contaminated with 10 mg DON/kg feed; 3) basal diet contaminated with 10 mg DON/kg feed and supplemented with 2.5 kg/ton of feed of Mycofix Select; 4) basal diet supplemented with Mycofix Select (2.5 kg/ton of feed). At the end of the feeding trial, blood were collected for measuring the level of lymphocyte DNA damage of blood and the TBARS level was measured in plasma, heart, kidney, duodenum and jejunum. The dietary exposure of DON caused a significant increase (P = 0.001) of DNA damage in blood lymphocytes (31.99±0.89%) as indicated in the tail of comet assay. Interestingly addition of Mycofix Select to DON contaminated diet decreased (P = 0.001) the DNA damage (19.82±1.75%) induced by DON. In order to clarify the involvement of lipid peroxidation in the DNA damage of DON, TBARS levels was measured. A significant increase (P = 0.001) in the level of TBARS (23±2 nmol/mg) was observed in the jejunal tissue suggesting that the lipid peroxidation might be involved in the DNA damage. The results indicate that DON is cytotoxic and genotoxic to the chicken intestinal and immune cells and the feed additive have potential ability to prevent DNA damage induced by DON.

In vitro determination of the anti-aging potential of four southern African medicinal plants

Background

Aging is an inevitable process for all living organisms. During this process reactive oxygen species generation is increased which leads to the activation of hyaluronidase, collagenase and elastase, which can further contribute to skin aging. Four southern African medicinal plants; Clerodendrum glabrum, Schotia brachypetala, Psychotria capensis and Peltophorum africanum, were investigated to assess their anti-aging properties.

Methods

Anti-elastase, anti-collagenase and anti-hyaluronidase activities of twenty-eight samples, consisting of methanol and ethyl acetate extracts of the four plants, were determined using spectrophotometric methods. Radical scavenging activity was determined by the ability of the plant extracts to scavenge the ABTS^•+ radical.

Results

The majority of the samples in the anti-elastase assay and nine in the anti-collagenase assay showed more than 80% inhibition. The ethyl acetate extract of S. brachypetala bark and leaves of P. capensis inhibited elastase activity by more than 90%. The methanol extract of S. brachypetala bark contained the highest anti-hyaluronidase activity (75.13 ± 7.49%) whilst the ethyl acetate extract of P. africanum bark exhibited the highest antioxidant activity (IC₅₀: 1.99 ± 0.23 μg/ml).

Conclusion

The free radical scavenging activity and enzyme inhibitory activity of the plant extracts investigated suggests that they can help restore skin elasticity and thereby slow the wrinkling process. P. africanum was the plant with the most promising activity and will be subjected to further testing and isolation of the active compound/s.

Toxicology of some important medicinal plants in southern Africa

Africa is home to two major floral kingdoms: the Paleotropical kingdom of central Africa and the Capensis kingdom of the Western Cape province of South Africa, the latter of which consists of approximately 10,000 species, representing about 20% of Africa's floral 'gold mine', better known as the Cape herbal medicine. Needless to say, such rich flora comes with numerous plants with a potential to cause poisoning to humans. This review document reports important toxic medicinal plants and their toxic ingredients for plant species resident in the southern African region. These include important medicinal uses and pharmacological properties ranging from antimicrobial, antiviral, anticancer, anti-inflammatory as well as those that are used as aphrodisiacs and for maternal health care.

Investigation of in vitro and in vivo anti-asthmatic properties of Siphonochilus aethiopicus

AIM OF THE STUDY

Asthma is a chronic inflammatory disease of the lungs, characterized by increased sensitivity to bronchoconstriction associated with infiltration of immune cells, mucus hypersecretion and structural remodelling of the airways. In South Africa, the indigenous plant Siphonochilus aethiopicus, is used by traditional health practitioners to treat colds, wheezing of the chest, coughs, influenza, sinus problems and mild asthma. In this study we aimed to investigate the potential anti-inflammatory and anti-allergic properties of S. aethiopicus in vitro and its efficacy in a mouse model of allergic asthma.

MATERIALS AND METHODS

The dried and powdered S. aethiopicus plant material was extracted separately with organic solvents (diethyl ether, ethanol) and water. Dried extracts as well as a purified furanoterpenoid compound present in the extracts were screened in vitro in a glucocorticoid and histamine H(1) receptor binding assay and a phosphodiesterase IV enzyme inhibition assay. Extracts were also evaluated for efficacy against ovalbumin (OVA)-induced allergic airway disease in mice.

RESULTS

Biological assaying of extracts of the plant and the isolated furanoterpenoid showed significant in vitro inhibition of glucocorticoid and histamine H(1) receptor binding and phosphodiesterase IV activity, supporting a possible anti-inflammatory, anti-allergic and bronchodilatory effect. Administration of S. aethiopicus extracts to OVA-sensitized and challenged mice significantly reduced lung inflammation and the percentage of eosinophils in bronchoalveolar lavage fluid but did not influence airway hyperreactivity.

CONCLUSION

This study provides evidence that S. aethiopicus has anti-inflammatory and anti-allergic properties in vitro and in vivo. These findings may support anecdotal accounts of its effectiveness against asthma, sinusitis, colds and flu.

The ability of Warburgia salutaris extracts to protect against crystalline silica-induced cell injury

In Southern Africa, the medicinal plant Warburgia salutaris is commonly used for the treatment of inflammatory and other diseases. The methanol extracts of W. salutaris were investigated with regard to a) production of proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interferon-γ; b) activation of the transcription factor nuclear factor kappa B; and c) induction of deoxyribonucleic acid (DNA) damage and lipid peroxidation in the presence of crystalline silica particles. Due to its antioxidant properties, extracts of W. salutaris showed protective effects against crystalline silica-induced inflammatory cytokine expression, activation of nuclear transcription factor-κB, DNA strand breakage, and lipid peroxidation. Hence, W. salutaris may be a potential therapeutic agent against the fibrogenic and carcinogenic effects of crystalline silica.

South African traditional medicinal plant trade-Challenges in regulating quality, safety and efficacy

Based on the long history of medicinal plant use, users of traditional medicines accept that they are safe for human consumption. However, the absence of regulation of the medicinal plant trade in aspects such as collection, processing and storage provides no such guarantee. Environmental pollution, misidentification and adulteration provides further grounds for concern. The potential adverse effects of South African traditional medicines are not well documented. There are only a few investigations of mutagenic properties and heavy metal contamination. In the absence of regulatory controls, the safety and quality of medicinal plants vary considerably. The current comprehension and future challenges regarding quality, safety and efficacy of South African traditional medicine are discussed.

Polymorphism of detoxification genes and cell resistance to mutagens in patients with Ehlers-Danlos syndrome

Study of polymorphism in 3 genes of the glutathione S-transferase family (GSTM1, GSTT1, and GSTP1) in children with Ehlers-Danlos syndrome whose cells were defective in repair of gamma-induced DNA damages revealed accumulation of GSTM1(+) genotypes compared to children of the control group. Generation of reactive oxygen species by neutrophils from patients with this syndrome was higher than in healthy donors. Our results indicate that glutathione S-transferase genes are involved in the resistance to mutagenic agents and demonstrate medical and genetic peculiarities of patients with Ehlers-Danlos syndrome.