Antioxidant activities of some cameroonian plants extracts used in the treatment of intestinal and infectious diseases

Ricinodendron heudelotii (Euphorbiaceae) seed oil prevents DMBA-induced breast cancer under menopause-like conditions in Wistar rats

Despite efforts, breast cancer remains associated with a high incidence and mortality rate. Ricinodendron heudelotii also known as "Njansang," is a plant used for cancer treatment. While several reports on the anticancer potential of its leaves exist, little is known about its seed oil. This study aimed to evaluate the in vitro and in vivo anti-breast cancer activity of "Njansang" seed oil. The inhibitory effect of "Njansang" seed oil was determined using MTT and CCK-8 dye reduction assays. Breast cancer was induced with DMBA and promoted with E2V (1 mg/kg) for 4 weeks in ovariectomized rats (menopausal condition). Evaluated parameters included tumor incidence, tumor mass and volume, histopathology, breast cancer biomarker CA 15-3, antioxidant status (CAT, GSH, MDA, NO, SOD), TNF-α and INFγ levels, lipid profile (total cholesterol, LDL-cholesterol, triglycerides and HDL-cholesterol), as well as toxicity parameters (ALT, AST, creatinine). "Njansang" oil significantly reduced the growth of ER+ (MCF-7) and triple negative (MDA-MB 231) adenocarcinoma cells in vitro as well as tumor incidence, tumor mass and CA 15-3 levels in vivo. It exhibited antioxidant activity, characterized by an increase in SOD and catalase activities, GSH levels and decreased MDA levels compared to the DMBA group. TNF-α and INF-γ levels were reduced following oil treatment, while total cholesterol, LDL-cholesterol and triglyceride levels were reduced. The aforementioned findings confirm the protective effects of "Njansang" oil on induced breast cancer in ovariectomized rats.

Seriphidium herba-alba (Asso): A comprehensive study of essential oils, extracts, and their antimicrobial properties

Seriphidium herba-alba (Asso), a plant celebrated for its therapeutic qualities, is widely used in traditional medicinal practices throughout the Middle East and North Africa. In a detailed study of Seriphidium herba-alba (Asso), essential oils and extracts were analyzed for their chemical composition and antimicrobial properties. The essential oil, characterized using mass spectrometry and retention index methods, revealed a complex blend of 52 compounds, with santolina alcohol, α-thujone, β-thujone, and chrysanthenone as major constituents. Extraction yields varied significantly, depending on the plant part and method used; notably, methanol soaking of aerial parts yielded the most extract at 17.75%. The antimicrobial analysis showed that the extracts had selective antibacterial activity, particularly against Staphylococcus aureus, and broad-spectrum antifungal activity against organisms such as Candida albicans and Aspergillus spp. The methanol-soaked extract demonstrated the strongest antimicrobial properties, indicating its potential as a natural antimicrobial source. This study not only underscores the therapeutic potential of Seriphidium herba-alba (Asso) in pharmaceutical applications but also sets a foundation for future research focused on isolating specific bioactive compounds and in vivo testing.

Chemical composition and biological activities of Pittosporum eriocarpum Royle: an unexplored medicinal plant of Indian himalayan region

In this study, different parts (leaf, bark, and fruit) of Pittosporum eriocarpum were investigated to explore its chemical composition and biological activities. The GC-MS analysis confirmed the presence of fifty-seven, eighty-one, and forty-six compounds in leaf, fruit, and bark extract, respectively. The important identified bioactive compounds include 1,3,4,5-tetrahydroxy-cyclohexanecarboxylic acid (quinic acid), falcarinol, tetradecanoic acid, and isopropyl myristate. Further, four polyphenolic compounds namely p-coumaric, chlorogenic, ferulic acid, and catechin were also identified and quantified in different parts through HPLC-PDA analysis. Of the studied parts of P. eriocapum, leaf extract contains the highest total phenolic, flavonoid, and tannin content, and exhibited potent antioxidant activity in ABTS assay. P. eriocarpum extracts also exhibited strong antimicrobial activity against gram-negative bacteria and showed considerable high protection against free radical-mediated DNA damage. To the best of our knowledge, this is the first detailed study of the chemical composition and biological activities of P. eriocarpum.

Ethnomedicinal uses, phytochemistry, and pharmacology of the genus Vepris (Rutaceae): A review

ETHNOPHARMACOLOGICAL RELEVANCE

Species of the genus Vepris are used in traditional African pharmacopeia for the treatment of various conditions, including chronic diseases and other parasitic. Further uses are against whooping cough and colic in children and as an antidote against snakebite. Data presented will enable the interested scientists to work on this genus applying the so-called "ethnopharmacologic approach", which may lead towards the discovery of the effective, safe plant medicinal products.

AIM OF THE REVIEW

This review article aims to collate and analyse the available information on the traditional uses, phytochemistry, pharmacology, and toxicological aspects of Vepris species in order to explore the trends and perspectives for further studies.

METHODOLOGY

The present review paper collected the literature published prior to August 2020 on the ethnomedicinal uses, phytochemistry, and pharmacology of the genus Vepris. The available information about the genus Vepris was collected via Google Books, Google Scholar, PubMed, ScienceDirect, SciFinder, Web of Science, and other internet sources. The Global Biodiversity Information Facility (www.gbif.org), Plants of the world online (www.plantsoftheworldonline.org), and The Plant List (www.theplantlist.org) databases were used to verify the scientific names and provide distribution information of Vepris species.

RESULTS

Comprehensive analysis of the literature provided information on ethnopharmacological uses of 30 species out of 83 members in the genus. A total of 213 compounds - predominantly alkaloids - were reported together with results from antioxidant, cytotoxic, antimicrobial, antiplasmodial, antitrypanosomal, antileishmanial, antidiabetic, antipyretic, analgesic, insect antifeedant, and toxicity assays. Arborinine (49) and skimmianine (4) isolated from the leaves of V. trichocarpa were tested toxic in rat skeletal myoblast cell line L6, a stable skeletal muscle progenitor cell line, while the leaves of V. heterophylla, the stem bark of V. louisii, and the roots of V. uguenensis were shown to be toxic against model organisms T. castaneum (Tenebrionidae), H. bakeri (Trychostrongylidae), and M. domestica (Muscidae), respectively. In addition, 6,7-methylenedioxy-5-hydroxy-8-methoxy-dictamnine (40) isolated from the leaves of a combined sample of V. renieri + V. suaveolens displayed an extremely low IC₅₀ of 0.67 μM against the normal fibroblastic lung cell line MRC-5 indicating high toxicity. Thus, medical use of these plant parts, as well of the stem bark of V. verdoorniana used locally in poison fishing, should be avoided if alternative treatments exist. Furthermore, a good number of significantly in vitro bioactive compounds have been reported from the genus Vepris: against malaria and against microbial infections.

CONCLUSIONS

Various Vepris species were found to be used in traditional African pharmacopeia. However, few of these species were studied for their bioactive chemical constituents with even fewer bioassay-guided isolation studies being reported. Moreover, detailed pharmacological studies in animal models to explore their mode of action were not reported. Therefore, future studies should focus on these aspects. In addition, we would like to recommend further research on some significantly bioactive crude extracts that were identified in this review: V. leandriana; V. lanceolata; V. nobilis; and V. trichocarpa, as well as those plants reported to be used against chronic diseases.

Nutritional Value and Antimicrobial Activity of Pittosporum angustifolium (Gumby Gumby), an Australian Indigenous Plant

The indigenous endemic plant P. angustifolium has received attention for nutraceutical and therapeutic applications in Australia. This study investigates for the first time the nutritional value (macro- and micronutrients, minerals, trace elements, polyphenols, carotenoids, saponins and antioxidant capacity) and antimicrobial activity of different botanical parts of P. angustifolium, either collected from the wild or cultivated. Different botanical tissues, geographic location and growing condition (wild vs. cultivated) showed significant (p < 0.05) effects on the tested bioactive compounds, with the leaves having significantly (p < 0.05) higher levels than the stems. Saponins and polyphenols could be identified as the main bioactive compounds in the leaves with up to 4% per dry weight. The extracts of P. angustifolium leaves and stems showed strong antioxidant and antimicrobial activities, especially against Candida albicans. These activities correlated (R2 = 0.64-0.92; p < 0.05) with the levels of polyphenols and saponins, indicating their biologic potential. Findings from this study may provide information for future applications of P. angustifolium in the functional ingredient or nutraceutical industry.

Comparative Phytochemical Constituents and Antioxidant Activity of Wild and Cultivated Alepidea amatymbica Eckl & Zeyh

There is a need to scientifically validate the claim that wild species of medicinal plants are more potent than the cultivated plants. Thus, this study evaluated the phytochemical and antioxidant properties of wild and cultivated Alepidea amatymbica. Acetone, methanol, and water extracts of the rhizome of wild and cultivated A. amatymbica were evaluated for total phenol, flavonol, flavonoid, tannin, proanthocyanidin, saponin, and alkaloid contents using spectrophotometric methods. In vitro antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), ferric reducing antioxidant power (FRAP), nitric oxide (NO), and hydrogen peroxide assays. The wild extracts had higher phytochemical contents in most of the assays than cultivated extracts. Total phenol in the wild extracts ranged from 32.30 to 117.8 mg GAE/g with the acetone extracts having the highest content while the water extracts were the least. The range in the total phenol of the cultivated species was 66.46 to 98.44 mg GAE/g with the methanol extracts having the highest content while water extracts was the least. The flavonoid content ranged from 55.01 to 99.09 mg QE/g and from 48.65 to 67.32 mg QE/g for the wild and cultivated plants, respectively. The alkaloid contents ranged from 14.70 to 17.80% in the wild species while it ranged from 11.98 to 13.21% in the cultivated species. The wild species also showed higher antioxidant activities in most of the assays evaluated. This study has implications for both pharmacological and conservation purposes.

Anti-hyperalgesic activity of the aqueous and methanol extracts of the leaves of Pittosporum mannii Hook on CFA-induced persistent inflammatory pain

BACKGROUND

Previous study showed that aqueous (AEPM) and methanol (MEPM) extracts from the leaves of Pittosporum mannii have analgesic effects in acute pain models. The present study evaluates the acute and chronic anti-hypernociceptive and anti-inflammatory effects of AEPM and MEPM in a model of persistent inflammatory pain.

METHODS

The third day after induction of inflammatory pain by subplantar injection of 100 µL of CFA in Wistar rats, AEPM and MEPM were administered orally (75, 150 and 300 mg/kg/day) and their anti-hyperalgesic and anti-inflammatory effects were follow in acute (1-24 h) and chronic (for 14 days) treatments. At the end of the chronic treatment, oxidative stress and liver parameters were assessed. Effects of plant extracts were also evaluated on nociception induced by Phorbol 12-Myristate 13-Acetate (PMA) and 8-bromo 3',5'-cAMP (8-Br-cAMP) in mice.

RESULTS

AEPM and MEPM significantly reversed the mechanical hyperalgesia caused by CFA in acute and chronic treatment. Moreover, AEPM and MEPM also significantly reduced the nociception caused by PMA (60%) and 8-Br-cAMP (87%). Nevertheless, AEPM and MEPM failed to inhibit the paw edema caused by CFA. Plant extracts significantly reduced the nitric oxide content in the spinal cord and the plasmatic concentration of alanine aminotransferase. MEPM also significantly increased the glutathione content in the spinal cord.

CONCLUSION

AEPM and MEPM given orally are effective in inhibiting mechanical hyperalgesia in persistent inflammatory pain caused by CFA. Their mechanisms of action seem to involve an interaction with PKC, PKA and nitric oxide pathways. These extracts might be devoid of hepatotoxic effects.

Pittosporum viridiflorum Sims (Pittosporaceae): A review on a useful medicinal plant native to South Africa and tropical Africa

ETHNOPHARMACOLOGICAL RELEVANCE

Pittosporum viridiflorum Sims, a Pittosporaceae species, is used extensively in African traditional medicine (ATM) by various tribes. This review is an appraisal of the information concerning the description, distribution, conservation status, traditional uses, phytochemistry, pharmacology and toxicology of this species with the aim of reconciling it with its traditional use.

MATERIALS AND METHODS

A wide-ranging literature search was conducted using database platforms such as Scopus, Google Scholar, Web of Science, ScienceDirect, PubMed and books including local reports and thesis submissions.

RESULTS

Ten categories to which P. viridiflorum finds use in traditional medicine (TM) were found, and they include well-being, wounds, treatment of veterinary ailments, gastrointestinal and sexually transmitted diseases, kidney, circulatory and inflammatory disorders, as well as diseases such as cancer, tuberculosis, and malaria. Pharmacological tests conducted include those investigating antimicrobial, antidiarrhoeal, antimalarial, anticancer, anti-inflammatory, antioxidant and acaricidal properties. Promising activity was shown in a number of assays. Toxicological effects have also been reported from this species. However, it is recommended to conduct a detailed toxicological study, including genotoxicity, as this has not yet been evaluated. Compound(s) with antimalarial, anticancer and acaricidal properties have been isolated from P. viridiflorum.

CONCLUSIONS

The collective pharmacological and phytochemical properties of P. viridiflorum gives credence to the use of this plant species against various diseases in ATM, thus steering significant interest towards in vivo studies and further research.

Potential of Central, Eastern and Western Africa Medicinal Plants for Cancer Therapy: Spotlight on Resistant Cells and Molecular Targets

Cancer remains a major health hurdle worldwide and has moved from the third leading cause of death in the year 1990 to second place after cardiovascular disease since 2013. Chemotherapy is one of the most widely used treatment modes; however, its efficiency is limited due to the resistance of cancer cells to cytotoxic agents. The present overview deals with the potential of the flora of Central, Eastern and Western African (CEWA) regions as resource for anticancer drug discovery. It also reviews the molecular targets of phytochemicals of these plants such as ABC transporters, namely P-glycoprotein (P-gp), multi drug-resistance-related proteins (MRPs), breast cancer resistance protein (BCRP, ABCG2) as well as the epidermal growth factor receptor (EGFR/ErbB-1/HER1), human tumor suppressor protein p53, caspases, mitochondria, angiogenesis, and components of MAP kinase signaling pathways. Plants with the ability to preferentially kills resistant cancer cells were also reported. Data compiled in the present document were retrieved from scientific websites such as PubMed, Scopus, Sciencedirect, Web-of-Science, and Scholar Google. In summary, plant extracts from CEWA and isolated compounds thereof exert cytotoxic effects by several modes of action including caspases activation, alteration of mitochondrial membrane potential (MMP), induction of reactive oxygen species (ROS) in cancer cells and inhibition of angiogenesis. Ten strongest cytotoxic plants from CEWA recorded following in vitro screening assays are: Beilschmiedia acuta Kosterm, Echinops giganteus var. lelyi (C. D. Adams) A. Rich., Erythrina sigmoidea Hua (Fabaceae), Imperata cylindrical Beauv. var. koenigii Durand et Schinz, Nauclea pobeguinii (Pobég. ex Pellegr.) Merr. ex E.M.A., Piper capense L.f., Polyscias fulva (Hiern) Harms., Uapaca togoensis Pax., Vepris soyauxii Engl. and Xylopia aethiopica (Dunal) A. Rich. Prominent antiproliferative compounds include: isoquinoline alkaloid isotetrandrine (51), two benzophenones: guttiferone E (26) and isoxanthochymol (30), the isoflavonoid 6α-hydroxyphaseollidin (9), the naphthyl butenone guieranone A (25), two naphthoquinones: 2-acetylfuro-1,4-naphthoquinone (4) and plumbagin (37) and xanthone V1 (46). However, only few research activities in the African continent focus on cytotoxic drug discovery from botanicals. The present review is expected to stimulate further scientific efforts to better valorize the African flora.

Antibacterial and antibiotic resistance modulatory activities of leaves and bark extracts of Recinodindron heudelotii (Euphorbiaceae) against multidrug-resistant Gram-negative bacteria

Background

Recinodindron heudelotii (Euphorbiaceae) is a plant used in Africa, particularly in Cameroon to treat various ailments including bacterial infections. In this study, we evaluated the extracts of the leaves (RHL) and bark (RHB) of R. heudelotii for their antibacterial and antibiotic resistance modulating activities against 29 Gram-negative bacteria, including multidrug-resistant (MDR) phenotypes.

Methods

The broth micro-dilution assay was used to evaluate the antibacterial activity, and the antibiotic resistance modulating effects of the plant extracts.

Results

RHL displayed the most important spectrum of activity with minimal inhibitory concentrations (MICs) values ranging from 256 to 1024 μg/mL against 75.86% of the 29 tested bacteria strains while RHB was not active. RHL also showed killing effects with minimal bactericidal concentrations (MBCs) ranging from 256 to 1024 μg/mL. The activities of tetracycline and kanamycin associated with RHL were improved on 88.89% and 77.78% of the tested MDR bacteria, at MIC/2 at MIC/4 respectively, with 2 to 16-folds decreasing of MIC. This suggests the antibiotic resistance modulating effects of these antibiotics.

Conclusion

The present study provides data indicating a possible use of the leaves extract of Recinodindron heudelotii alone or in association with common antibiotics in the fight against bacterial infections including those involving MDR bacteria.

Ethnomedicinal Plants Used by Traditional Healers to Treat Oral Health Problems in Cameroon

Objectives. The objective of the study was to determine the therapeutic methods used by traditional healers to treat oral diseases in Cameroon. Methods. A total of 200 traditional healers with a mean age of 50.4 ± 14.2 years from all the provinces of Cameroon were studied using questionnaires. Information elicited was the local names of the medicinal plants used for the management of oral problems, their routes of administration, and methods of usage. Identification of live or dried plants or photographs of sample of the plants was done by a taxonomist. Results. The majority of the participants were males urban dwellers aged 41–50 years, 112 (56.0%) practice as herbalists and 56 (28.0%) were trained on medications preservation, 77(56.6%) treat diseases inside or outside the mouth, and 9.0% reported being specialist in oral diseases treatment. Of the 52 plants identified, 48 are used in the management of toothache, sore throat, mouth sores, abscess, broken tooth and jaw, tooth sensitivity, mouth thrush, dental caries, gingivitis, sinusitis, tonsillitis, xerostomia, oral syphilis, oral cancer, TMJ pain, halitosis, and tooth bleaching and 4 plants are used for dental extraction. Roots, leaves, and bark were the parts of plants used and some minerals as adjuncts. Conclusion. The study provides comprehensive information on therapeutic methods employed by traditional healers for the treatment of oral diseases.

Effects of the aqueous extract of Pittosporum mannii Hook. f. (Pittosporaceae) stem barks on spontaneous and spasmogen-induced contractile activity of isolated rat duodenum

ETHNOPHARMACOLOGICAL RELEVANCE

Pittosporum mannii Hook. f. (Pittosporaceae) is a plant widely used in traditional medicine in Cameroon for the treatment of many gastrointestinal disorders including diarrhea. To date, no pharmacological study on the antidiarrheal and the antispasmodic properties of this plant has been reported. The aim of the present study was to evaluate in vitro the relaxant activity of the aqueous extract of stem barks of P. mannii (PMAE) on rat duodenum.

MATERIALS AND METHODS

Different concentrations of PMAE were tested separately (10-80 µg/mL) or cumulatively (5-80 µg/mL) on spontaneous and spasmogen (carbachol, histamine and KCl)-induced contractions of isolated rat duodenum strips.

RESULTS

At concentrations ranging from 10 to 80 µg/mL, PMAE significantly decreased the tonus and the amplitude of spontaneous contractions. However, at high concentration (80 µg/mL), the extract elicited a transient relaxation was followed by a slight increase of tonus, while the amplitude remained lower compared to the normal spontaneous activity. The relaxant effect of the extract was not significantly affected in the presence of atropine (0.713 µg/mL) and promethazine (0.5 µg/mL). In addition, PMAE (20, 40, and 80 µg/mL) partially but significantly inhibited in a concentration related manner the contractions induced by carbachol (10(-9)-10(-4)M) and histamine (10(-9)-10(-4)M) on rat duodenum. PMAE (10-80 µg/mL) also significantly induced a concentration-dependent relaxation on KCl (20mM, 50mM, 10(-3)-6.10(-3)M)-induced contraction of rat duodenum.

CONCLUSIONS

These results show that the aqueous extract of P. mannii stem barks possesses antispasmodic and spasmolytic effects at lower concentrations; therefore, supporting the use of the stem barks of this plant in the folk medicine for the treatment of diarrhea. However, caution should be paid while using higher concentrations that instead might produce spasmogenic effect and might worsen the diarrheal condition. The relaxant effect of PMAE appears to be non-specific of muscarinic or histaminic receptors, but may involve at least in part a mechanism of inhibition of the Ca(2+) influx into the smooth muscle cells through voltage-operated Ca(2+) channels.

African flora has the potential to fight multidrug resistance of cancer

Background. Continuous efforts from scientists of diverse fields are necessary not only to better understand the mechanism by which multidrug-resistant (MDR) cancer cells occur, but also to boost the discovery of new cytotoxic compounds to fight MDR phenotypes. Objectives. The present review reports on the contribution of African flora in the discovery of potential cytotoxic phytochemicals against MDR cancer cells. Methodology. Scientific databases such as PubMed, ScienceDirect, Scopus, Google Scholar, and Web of Knowledge were used to retrieve publications related to African plants, isolated compounds, and drug resistant cancer cells. The data were analyzed to highlight cytotoxicity and the modes of actions of extracts and compounds of the most prominent African plants. Also, thresholds and cutoff points for the cytotoxicity and modes of action of phytochemicals have been provided. Results. Most published data related to the antiproliferative potential of African medicinal plants were from Cameroon, Egypt, Nigeria, or Madagascar. The cytotoxicity of phenolic compounds isolated in African plants was generally much better documented than that of terpenoids and alkaloids. Conclusion. African flora represents an enormous resource for novel cytotoxic compounds. To unravel the full potential, efforts should be strengthened throughout the continent, to meet the challenge of a successful fight against MDR cancers.

Antibacterial activities of Beilschmiedia obscura and six other Cameroonian medicinal plants against multi-drug resistant Gram-negative phenotypes

Background

The rapid spread of bacteria expressing multi-drug resistance propels the search for new antibacterial agents. The present study was designed to evaluate the antibacterial activities of the methanol extracts from Beilschmiedia obscura and six other Cameroonian plants against a panel of twenty nine Gram-negative bacteria including Multi-drug resistant (MDR) phenotypes.

Methods

The phytochemical investigations of the extracts were carried out according to the standard methods and the liquid micro-dilution assay was used for all antibacterial assays.

Results

Phytochemical analysis showed the presence of alkaloids in all studied extracts. Other chemical classes of secondary metabolites such as anthocyanines, anthraquinones flavonoids, saponins, tannins, sterols and triterpenes were selectively detected in the extracts. The extract from the fruits of Beilschmiedia obscura, Pachypodanthium staudtii leaves and Peperomia fernandopoiana (whole plant) displayed the best spectrum of activity with MIC values ranging from 16 to 1024 μg/mL against at least 65% and above of the tested bacteria. The extract from Beilschmiedia obscura was the most active with MIC values below 100 μg/mL against ten of the tested bacteria. This extract also showed MBC values below 1024 μg/mL against 55.17% of the studied microorganisms. Phenylalanine arginine β-naphthylamide (PAβN) significantly modulated the activities of extracts from the leaves and fruits of Pachypodanthium staudtii and Beilschmiedia obscura respectively, by increasing their inhibitory activity against Klebsiella pneumoniae KP55 strain at least four fold.

Conclusion

The overall results of the present investigation provide information for the possible use of the methanol extracts of the studied plant species, especially B. obscura to fight infectious diseases caused by Gram-negative bacteria including MDR phenotypes.

Cytotoxicity and Modes of Action of the Methanol Extracts of Six Cameroonian Medicinal Plants against Multidrug-Resistant Tumor Cells

Introduction. The present study aims at evaluating the cytotoxicity of twelve parts from six Cameroonian medicinal plants on sensitive and drug-resistant cancer cell lines. We also studied the mode of action of the most active plants, Gladiolus quartinianus, Vepris soyauxii, and Anonidium mannii. Methods. The cytotoxicity of the extracts was determined using a resazurin assay. Flow cytometry was used for cell-cycle analysis and detection of apoptosis, analysis of mitochondrial membrane potential (MMP), and measurement of reactive oxygen species (ROS). Results. At 40 g/mL, three extracts showed a growth of CCRF-CEM leukemia cells by less than 50%. This includes the extracts from G. quartinianus (GQW; 25.69%), Vepris soyauxii leaves (VSL; 29.82%), and Anonidium mannii leaves (AML; 31.58%). The lowest IC₅₀ values below 30 μg/mL were obtained with GQW, AML and VSL against 7/9, 8/9, and 9/9 tested cancer cell lines, respectively. The lowest IC₅₀ values for each plant were 4.09 μg/mL, and 9.14 μg/mL (against U87MG.ΔEGFR cells), respectively, for VSL and AML and 10.57 μg/mL (against CCRF-CEM cells) for GQW. GQW induced cell cycle arrest between G0/G1 and S phases, whilst VSL and AML induced arrest in G0/G1. All three extracts induced apoptosis in CCRF-CEM cells by loss of MMP, whilst AML also enhanced production of ROS. Conclusion. The three active plants may be a source for the development of new anticancer drugs.

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.