Flavonoids of Chromolaena odorata (L.) R.M.King & H.Rob. as potential leads for treatment against tuberculosis.

Tuberculosis (TB) is currently rated as the 13th leading cause of mortality and the second leading cause of death after COVID-19, and above AIDS. Existing challenges relating to the development of multidrug-resistant strains and dangerous side effects of currently used drugs add impetus to the search for additional TB treatments. Hence, interest has grown in the use of medicinal plants as a source of bioactive preparations with efficacy against TB-causing organisms, and also with the ability to ameliorate the negative effects of TB drugs. This study aimed to evaluate the antimycobacterial and hepatoprotective potentials of extracts and isolated flavonoid compounds from invasive Chromolaena odorata. Test organisms used were pathogenic Mycobacterium bovis and M. tuberculosis H37RV, and the fast-growing M. aurum, M. fortuitum and M. smegmatis. The selectivity index (SI) values of the test substances were determined through cytotoxicity assays to promote these extracts and compounds as leads for the development of effective and safe anti-tubercular drugs. The antimycobacterial activity was evaluated using a serial microdilution method, and the SI was calculated from the 50% lethal concentrations calculated from cytotoxicity tests. Hepatoprotective activity was determined using HepG2 liver cells treated with rifampicin as a toxin. The extracts and compounds had a range of antimycobacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.031 to 2.5 mg/mL. Two flavonoid compounds, 5,7,4'-trimethoxy flavanone and 5­hydroxy-3,7,4'-trimethoxyflavone showed promising antimycobacterial potential, and minimal toxicity was observed, as most SI values were higher than 1. The flavonoid compound 5,7,4'-trimethoxy flavanone had the highest SI (6.452), which was against M. tuberculosis H37RV. The HepG2 cells were reduced to 65% due to toxicity by rifampicin, however, the flavonoid compounds were able to improve cell viability to between 81 and 89% at different concentrations tested. Results obtained indicate that C. odorata may serve as a lead for the development of safe and effective antimycobacterial and hepatoprotective drugs.

Ethnopharmacology and biological activities of the Aizoaceae.

ETHNOPHARMACOLOGICAL RELEVANCE: The Aizoaceae is one of the largest succulent plant families. Most members of the family are ornamental and form part of specialist succulent collections. The exceptional diversity of the Aizoaceae is not only limited to its growth forms, habitat, and chemistry, but is also reflected in its many traditional uses. Selected species are well known for their use in traditional medicines, with recent scientific studies validating their biological activity. AIM OF THE STUDY: Herein, this review aimed to articulate foundational and current global research endeavors related to the traditional uses and pharmacological activities of the Aizoaceae. MATERIALS AND METHODS: Research articles and search terms related to the ethnopharmacology and bioactivities of the Aizoaceae between 1940 and 2022 were evaluated using electronic databases such as Google Scholar, PubMed, ScienceDirect, Scopus, JSTOR, and Web of Science. RESULTS: Popular Aizoaceae genera including Mesembryanthemum, Trianthema, and Tetragonia are noted for their cultural value and are key components in herbal medicines for the treatment of a myriad of disorders. Isolated bioactive compounds isolated from selected species demonstrated varied antimicrobial, antioxidant, and neuroprotective functions in basic pharmacological studies. However, most studies lacked reliable correlation to in vivo activity and did not adequately validate the safety and efficacy of potential therapeutic compounds. CONCLUSIONS: While the cultural and therapeutic value of popular Aizoaceae species have been highlighted in the literature, there remains glaring inconsistencies among other related species. Data deficiency may be ameliorated by further studies focused on taxonomic markers, chemical characterization and underlying molecular mechanisms of activity of a wider pool of species to enhance our knowledge of this hyperdiverse family.

Invasive alien plants and weeds in South Africa: A review of their applications in traditional medicine and potential pharmaceutical properties.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional pharmacopoeias are constantly evolving and adapting, hence the assimilation of alien plants and weeds into traditional systems of healing. Invasive plants are detrimental to the ecosystem, however they are also potential sources of secondary metabolites with useful biological activities. AIM OF THE REVIEW: The aim of this review was to investigate published reports of traditional use and biological activity of declared invasive alien plants and other weeds in South Africa. MATERIALS AND METHODS: Information was retrieved from scientific databases including Scopus, Web of Science, ScienceDirect, Google Scholar, PubMed, Chemical Abstracts Services and books, theses, dissertations and technical reports. Keywords used for the search engines were "South Africa" or "southern Africa" in conjunction with "(native weeds OR alien invasive)" AND "medicinal". Separate searches were conducted on the individual invasive plant species recorded as having been used in ethnobotanical surveys to determine their known biological activities and chemical components. RESULTS: A total of 89 plant species regarded as invasive species or weeds in South Africa were identified as being used in traditional medicine. The most commonly mentioned plant family was the Asteraceae with a total of 15 species followed by the Fabaceae and Solanaceae with 6 species each. Of the 89 species recorded, 68% were reported to have traditional usage with both phytochemical and biological data available. A history of traditional usage coupled with biological data was available for 12% of species. Records of traditional usage alone were linked to 11% of species. Invasive alien species comprised 61% of recorded species, while native and non-invasive alien weeds formed the remaining 39%. CONCLUSIONS: The exploration of alternative uses for weeds and particularly invasive plants, whether native or alien, as medicines for possible commercialisation may lead to innovative mechanisms for putting such species to good use.

Bioassay-guided purification, GC-MS characterization and quantification of phyto-components in an antibacterial extract of Searsia lancea leaves.

Phytocompounds in an aqueous methanol (70% MeOH) leaf extract of Searsia lancea were separated using liquid-liquid partitioning techniques and gravity-assisted column chromatography. The resultant fractions were screened for antibacterial properties (minimum inhibitory concentration, MIC) against four bacterial strains (Enterococcus faecalis, Klebsiella pneumoniae, Neisseria gonorrhoeae and Staphylococcus aureus). Bioactive fractions were purified using preparative thin layer chromatography (TLC) and subjected to further antibacterial screening. Phytocompounds in antibacterial sub-fractions were characterized and quantified using Gas Chromatography-Mass Spectrometry (GC-MS). An ethyl acetate sub-fraction purified from the aqueous methanol extracts of the leaves demonstrated potent antibacterial properties (MIC range: 31-61 µg/ml against E. faecalis and S. aureus). Based on GC-MS analysis, 81.5% of the sub-fraction consisted of broad-spectrum antibacterial compounds namely tetracosanol (43.98%) and nonadecanol (37.5%). Current research findings support the traditional use of S. lancea leaves to manage gastro-intestinal disorders and gonorrhoea.

Validation of a Monte Carlo modelled gamma camera for Lutetium-177 imaging.

This study validated a model of the Siemens Symbia T16 dual-head SPECT/CT gamma camera created using the Monte Carlo program SIMIND for 177Lu. The validation was done by comparing experimental and simulated gamma camera performance criteria tests for the 177Lu 208 keV photopeak with a medium-energy collimator. Results showed good agreement between the experimental and simulated values. These results illustrated that SIMIND could emulate the Symbia T16 successfully and therefore, can be used with confidence to model 177Lu images.

New role for crinamine as a potent, safe and selective inhibitor of human monoamine oxidase B: In vitro and in silico pharmacology and modeling.

ETHNOPHARMACOLOGICAL RELEVANCE: The development of selective inhibitors of monoamine oxidase B (MAO-B) has been essential in treating Parkinson's disease. However, the apparent hepatotoxicity and drug-drug interactions of current inhibitors accentuate the need for the development of novel pharmacotherapies. Crossyne guttata (L.) D. & U. Müll-Doblies is used frequently by Rastafarian bush doctors to treat alcoholism, a disorder which is also accentuated by MAO. OBJECTIVE: The study sought to isolate, identify and characterise the biologically active constituents of C. guttata based on their ability to inhibit the MAO enzymes. MATERIALS AND METHODS: Column chromatography was used to isolate the biologically active alkaloids of C. guttata. The ability of the alkaloids to inhibit the biotransformation of 4-aminoantipyrine by the MAO enzymes was evaluated in vitro. In silico docking was conducted using AutoDock Vina server while the pharmacokinetic properties of the compounds were evaluated using SwissADME. RESULTS: Chromatographic separation of an ethanolic fraction of C. guttata yielded the alkaloids crinamine 1 and epibuphanisine 2. 1 and 2 along with structurally related alkaloids haemanthamine 3 and haemanthidine 4 were evaluated for their ability to inhibit the action of isozymes of MAO in vitro. Alkaloids effected submicromolar IC50 values against MAO-B, the most potent of which being crinamine 1 (0.014 µM) > haemanthidine 4 (0.017 µM) > epibuphanisine 2 (0.039 µM) > haemanthamine 3 (0.112 µM). Binding energies of the alkaloids correlated well with their inhibitory potential with crinamine displaying the best binding efficacy and binding energy score with MAO-B. DISCUSSION AND CONCLUSION: Crinamine and epibuphanisine exhibited potent and selective inhibitory activity towards MAO-B. After comprehensive in silico investigations encompassing robust molecular docking analysis, the drug-like attributes and safety of the alkaloids suggest the crinamine is a potentially safe drug for human application.

Strigolactones and their crosstalk with other phytohormones.

BACKGROUND: Strigolactones (SLs) are a diverse class of butenolide-bearing phytohormones derived from the catabolism of carotenoids. They are associated with an increasing number of emerging regulatory roles in plant growth and development, including seed germination, root and shoot architecture patterning, nutrient acquisition, symbiotic and parasitic interactions, as well as mediation of plant responses to abiotic and biotic cues. SCOPE: Here, we provide a concise overview of SL biosynthesis, signal transduction pathways and SL-mediated plant responses with a detailed discourse on the crosstalk(s) that exist between SLs/components of SL signalling and other phytohormones such as auxins, cytokinins, gibberellins, abscisic acid, ethylene, jasmonates and salicylic acid. CONCLUSION: SLs elicit their control on physiological and morphological processes via a direct or indirect influence on the activities of other hormones and/or integrants of signalling cascades of other growth regulators. These, among many others, include modulation of hormone content, transport and distribution within plant tissues, interference with or complete dependence on downstream signal components of other phytohormones, as well as acting synergistically or antagonistically with other hormones to elicit plant responses. Although much has been done to evince the effects of SL interactions with other hormones at the cell and whole plant levels, research attention must be channelled towards elucidating the precise molecular events that underlie these processes. More especially in the case of abscisic acid, cytokinins, gibberellin, jasmonates and salicylic acid for which very little has been reported about their hormonal crosstalk with SLs.

Ethnobotany, phytochemistry, toxicology and pharmacological properties of Terminalia sericea Burch. ex DC. (Combretaceae) - A review.

ETHNOPHARMACOLOGICAL REFERENCE: The use of medicinal plants in the treatment of infections is ancient. A wide variety of ethnotherapeutic properties and pharmacological actions has been attributed to Terminalia sericea. Studies by various groups of investigators reveal that it is a multipurpose medicinal plant used mostly in the treatment of diarrhoea, sexually transmitted infections, skin rashes, tuberculosis and other infections. The current paper is aimed at providing an overview of the ethnomedicinal uses, toxicology, pharmacology and the phytochemistry of Terminalia sericea. MATERIALS AND METHODS: Information was retrieved using various search engines, including Pubmed, Science Direct, Google Scholar, Scielo, SciFinder and Scopus. The key words used included Terminalia sericea, secondary metabolites, phytochemistry, biological activity, pharmacology, ethnobotanical survey, medicinal uses, safety, toxicology and other related words. RESULTS: Terminalia sericea is an important medicinal plant which possesses anti-HIV, anti-fungal, anti-bacterial, anticancer, lipolytic, wound healing, antiparasitic, anti-inflammatory and anti-oxidant activity, as the most valuable biological activities, thus lending pharmacological support to the plant's folkloric uses in indigenous medicine. Toxicologically, the extracts and isolated compounds from the plant species may have mild toxic effects. Phytochemically, the plant species possesses valuable compounds including triterpenes, alkaloids and flavonoids which may well contribute to its biological activity. CONCLUSIONS: Terminalia sericea contains secondary metabolites which are valuable in the treatment of a variety of human infections, including community acquired infections which may be prevalent in developing countries. The degree of toxicity reported in various extracts warrants further exploration of the cytotoxicity of the plant species, both against normal human cell lines and in vivo. Moreover, the acetylcholinesterase inhibitory and anti-inflammatory effects also need to be further investigated as there are only a few reports from the literature on these aspects. There is also a need to further understand the mode of action of the extracts against various enzymes relating to inflammation. Antioxidant activity of the plant extracts against various forms of free radicals needs to be investigated. Although T. sericea is reported to be used for ethnoveterinary infections, there are no scientific reports on the anti-parasitic activity of the plant species against common animal parasites.

Investigating the effect of cadmium and aluminium on growth and stress-induced responses in the micropropagated medicinal plant Hypoxis hemerocallidea.

Hypoxis hemerocallidea is a highly utilized medicinal plant in South Africa. Its cultivation has received considerable attention in order to meet the high demand. High levels of cadmium (Cd) and aluminum (Al) in H. hemerocallidea plants sold in traditional medicinal markets was previously reported. The present study used an in vitro propagation model to investigate the uptake of Cd and Al by H. hemerocallidea and their effect on plant growth, elemental uptake and some stress-induced responses such as pigment, malondialdehyde (MDA), proline content and ultrastructural changes. Shoot and root growth of plantlets exposed to Cd, Cd:Al and high concentrations of Al was significantly reduced. Highest concentrations of Cd accumulated in the corms of Cd-treated plantlets while highest Al concentrations occurred in the leaves and roots. There was higher accumulation of Cd and Al when applied singularly compared to the Cd:Al combination treatments. Cd and Al also reduced accumulation of trace elements in micropropagted H. hemerocallidea with lowest concentrations in the Cd:Al combination treatments. Exposure to Cd, Al and Cd:Al significantly reduced the level of chlorophyll but increased the levels of carotenoids, MDA and proline. Ultrastructural changes were also observed in H. hemerocallidea exposed to Cd and Al. All these factors contributed to the inhibition of plant growth and could potentially affect the ability of this important medicinal plant to synthesize bioactive compounds. It is thus necessary to understand heavy metal stress-induced responses in this highly valued medicinal plant to ensure a high quality product for the consumer.

The effects of smoke derivatives on in vitro seed germination and development of the leopard orchid Ansellia africana.

Plant-derived smoke and smoke-isolated compounds stimulate germination in seeds from over 80 genera. It has also been reported that smoke affects overall plant vigour and has a stimulatory effect on pollen growth. The effect of smoke on orchid seeds, however, has not been assessed. In South Africa, orchid seeds from several genera may be exposed to smoke when they are released from their seedpods. It is therefore possible that smoke may affect their germination and growth. Therefore, the effects of smoke [applied as smoke-water (SW)] and two smoke-derived compounds, karrikinolide (KAR1 ) and trimethylbutenolide (TMB), were investigated on the germination and growth of orchid seeds in vitro. The effect of SW, KAR1 and TMB were investigated on the endangered epiphytic orchid, Ansellia africana, which is indigenous to tropical areas of Africa. Smoke-water, KAR1 and TMB were infused in half-strength MS medium. The number of germinated seeds and number of seeds and protocorm bodies to reach predetermined developmental stages were recorded on a weekly basis using a dissecting microscope for a 13-week period. Infusing SW 1:250 (v:v) into half-strength MS medium significantly increased the germination rate index (GRI) and the development rate index (DRI) of the A. africana seeds. All the SW treatments significantly increased the number of large protocorm bodies at the final stage of development. Infusing KAR1 into the growing medium had no significant effect on germination or development of the seeds. The TMB treatment, however, significantly reduced the GRI and DRI of A. africana seeds.

Accumulation pattern of endogenous cytokinins and phenolics in different organs of 1-year-old cytokinin pre-incubated plants: implications for conservation.

A better understanding of phytohormone physiology can provide an essential basis to coherently achieve a conservation drive/strategy for valuable plant species. We evaluated the distribution pattern of cytokinins (CKs) and phenolic compounds in different organs of 1-year-old greenhouse-grown Tulbaghia simmleri pre-treated (during micropropagation) with three aromatic CKs (benzyladenine = BA, meta-topolin = mT, meta-topolin riboside = mTR). The test species is highly valuable due to its medicinal and ornamental uses. Based on UHPLC-MS/MS quantification, mT and mTR pre-treated plants had the highest total CK, mostly resulting from the isoprenoid CK-type, which occurred at highest concentrations in the roots. Although occurring in much lower concentrations when compared to isoprenoid CKs, aromatic CKs were several-fold more abundant in the root of mT pre-treated plants than with other treatments. Possibly related to the enhanced aromatic CKs, free bases and ribonucleotides, plants pre-treated with mT generally displayed better morphology than the other treatments. A total of 12 bioactive phenolic compounds, including four hydroxybenzoic acids, five hydroxycinnamic acids and three flavonoids at varying concentrations, were quantified in T. simmleri. The occurrence, distribution and levels of these phenolic compounds were strongly influenced by the CK pre-treatments, thereby confirming the importance of CKs in phenolic biosynthesis pathways.

Effect of smoke derivatives on in vitro pollen germination and pollen tube elongation of species from different plant families.

Plant-derived smoke stimulates seed germination in numerous plant species. Smoke also has a positive stimulatory effect on pollen germination and pollen tube growth. The range of plant families affected my smoke still needs to be established since the initial study was restricted to only three species from the Amaryllidaceae. The effects of smoke-water (SW) and the smoke-derived compounds, karrikinolide (KAR1 ) and trimethylbutenolide (TMB) on pollen growth characteristics were evaluated in seven different plant families. Smoke-water (1:1000 and 1:2000 v:v) combined with either Brewbaker and Kwack's (BWK) medium or sucrose and boric acid (SB) medium significantly improved pollen germination and pollen tube growth in Aloe maculata All., Kniphofia uvaria Oken, Lachenalia aloides (L.f.) Engl. var. aloides and Tulbaghia simmleri P. Beauv. Karrikinolide (10(-6) and 10(-7) m) treatment significantly improved pollen tube growth in A. maculata, K. uvaria, L. aloides and Nematanthus crassifolius (Schott) Wiehle compared to the controls. BWK or SB medium containing TMB (10(-3) m) produced significantly longer pollen tubes in A. maculata, K. uvaria and N. crassifolius. These results indicate that plant-derived smoke and the smoke-isolated compounds may stimulate pollen growth in a wide range of plant species.

Isolation and characterization of antimicrobial compounds from Terminalia phanerophlebia Engl. & Diels leaf extracts.

ETHNOPHARMACOLOGICAL RELEVANCE: The emergence of drug resistant-tuberculosis and other pathogenic diseases over the past decades, constitutes a serious threat to human health worldwide. According to a 2012 report by the World Health Organization (WHO), South Africa, China, India and Russia are the countries with the highest prevalence of Multi-Drug Resistant tuberculosis (MDR-tuberculosis) as they represented 60% of the total. Several reports have documented antimycobacterial properties of Terminalia species but only a few species from this genus have been explored for their antimycobacterial constituents. The crude extracts of Terminalia phanerophlebia showed good antimicrobial activities in our previous study against two Mycobacterium as well as two other bacterial strains responsible for opportunistic infections related to respiratory ailments. This paper studies the isolation of compounds responsible for such activities and to isolate compounds responsible for antimicrobial activities from the crude extracts of Terminalia phanerophlebia leaves. MATERIALS AND METHODS: Terminalia phanerophlebia crude extracts obtained from 80% methanol was successively extracted with hexane, dichloromethane (DCM), ethyl acetate (EtOAc) and n-butanol. The fractions obtained and isolated compounds were tested for their antibacterial activities against Mycobacterium aurum, Mycobacterium tuberculosis, Staphylococcus aureus and Klebsiella pneumoniae. Bioguided fractionation of the EtOAc fraction afforded two bioactive compounds. Structure elucidation was carried out using NMR (1D and 2D) spectroscopic methods. RESULTS: EtOAc fraction exhibited highest antimicrobial activities and its fractionation afforded methyl gallate (methyl-3,4,5-trihydroxybenzoate) (1) and a phenylpropanoid glucoside, 1,6-di-O-coumaroyl glucopyranoside (2) These compounds are reported from Terminalia phanerophlebia for the first time. Both compounds showed good antimicrobial activity against all bacterial strains tested with minimum inhibitory concentration (MIC) values ranging from 63 to 250 µg/mL. Inhibition of Mycobacterium tuberculosis by 1,6-di-O-coumaroyl glucopyranoside (2) at a MIC value of 63 µg/mL was noteworthy, as this bacterial strain is reported to be the leading cause of tuberculosis worldwide. CONCLUSIONS: Good antimicrobial activities exhibited by the compounds isolated from Terminalia phanerophlebia authenticate the traditional use of this plant in treating tuberculosis and its related symptoms. Compound (2), 1,6-di-O-coumaroyl glucopyranoside could serve as a lead compound for tuberculosis drug discovery.

Effect of light on growth and endogenous hormones in Chlorella minutissima (Trebouxiophyceae).

Plant growth regulators (PGRs) play an important role in mediating growth and stress responses in plants. Light influences PGRs concentrations in vascular plants. The effect of light on growth and endogenous PGR concentrations in microalgae was investigated in the present study. Chlorella minutissima MACC 360 was grown in 14:10 h light:dark (L:D), continuous dark (CD) and continuous dark with the addition of 5 g L(-1) glucose (CD + G) for 48 h. Cultures were synchronized in the L:D cultures, increasing in size during the light period and dividing during the dark period. C. minutissima cells did not increase in size or undergo cell division in CD cultures. In CD + G conditions, the cultures were no longer synchronized but did continue to increase in cell size and constantly underwent cell division although fewer cells divided than in the L:D cultures. Endogenous auxin and cytokinin concentrations increased and gibberellin concentrations decreased over time in the actively growing cultures (L:D and CD + G) but did not increase in the CD cultures. The largest increase in indole content was in the CD + G cultures while the L:D cultures had the largest cytokinin increase. Brassinosteroid concentrations decreased over time in all the cultures including those grown in CD conditions. Abscisic acid (ABA) concentrations were low and only increased in the CD cultures. These results show that endogenous PGRs were affected by the light regime and/or culture growth.

Antimycobacterial, anti-inflammatory and genotoxicity evaluation of plants used for the treatment of tuberculosis and related symptoms in South Africa.

ETHNOPHARMACOLOGICAL RELEVANCE: Emergence of drug-resistant tuberculosis strains and long duration of treatment has established an urgent need to search for new effective agents. The great floral diversity of South Africa has potential for producing new bioactive compounds, therefore pharmacological screening of plant extracts within this region offers much potential. To assess the in vitro antimycobacterial, anti-inflammatory and genotoxicity activity of selected plants that are used for the treatment of TB and related symptoms in South Africa. MATERIALS AND METHODS: Ground plant materials from 10 plants were extracted sequentially with four solvents (petroleum ether, dichloromethane, 80% ethanol and water) and a total of 68 extracts were produced. A broth microdilution method was used to screen extracts against Mycobacterium tuberculosis H37Ra. The cyclooxygenase-2 (COX-2) enzyme was used to evaluate the anti-inflammatory activity of the extracts and the Salmonella microsome assay using two Salmonella typhimurium strains (TA98 and TA100) to establish genotoxicity. RESULTS: Six out of 68 extracts showed good antimycobacterial activity. Three extracts showed good inhibition (>70%) of COX-2 enzyme. All the extracts tested were non-genotoxic against the tested Salmonella strains. CONCLUSION: The results observed in this study indicate that some of the plants such as Abrus precatorius subsp. africanus, Ficus sur, Pentanisia prunelloides and Terminalia phanerophlebia could be investigated further against drug-resistant TB strains.

Phytosynergy in some Hypoxis species and pharmacological properties of a Hypoxis-based phytopharmaceutical formula.

ETHNOPHARMACOLOGY RELEVANCE: Hypoxis species are used extensively in traditional medicine in southern Africa for several ailments including tuberculosis, chest infections, and nervous and urinary disorders. Several other claims have been made for extracts emanating from Hypoxis species and have led to the production of several commercial products used as immunostimulants mostly for people living with HIV/AIDS and cancer. This study was aimed at investigating the biological activity of four Hypoxis species and a commercial herbal product, 'African potato extract' (APE). MATERIALS AND METHODS: Antibacterial, antifungal, cyclooxygenase (COX) and acetylcholineasterase (AChE) inhibitory activities of four Hypoxis species (H. acuminata, H. colchicifolia, H. hemerocallidea and H. rigidula) and a popular Hypoxis-based herbal preparation, APE were tested. The phytoconstituents of the mixture were also profiled using TLC methods. Several combinations of the Hypoxis species were prepared and their synergism, additive, autonomic and antagonism effects investigated. As a quality control measure, batch to batch comparison in the phytoconstituents and biological activity of APE was carried out. RESULTS: The results confirmed H. colchicifolia and H. hemerocallidea as the phytoconstituents of APE. The extracts showed a broad spectrum of activities against the bacterial and fungal strains used. Of particular interest were the activities exhibited by the APE and combinations of H. colchicifolia and H. hemerocallidea. The APE mixture exhibited good antibacterial activity (MIC values of 0.78mg/ml each) in all the tested batches against the bacterial strains used. The water extracts of all four Hypoxis species, three batches of APE and the combination (water extracts) of H. colchicifolia and H. hemerocallidea exhibited high COX-1 and moderate COX-2 inhibitory activity except for H. acuminata which showed low activity against COX-2. All the extract, batches of APE and combinations showed low to moderate AChE inhibitory activity. These results provided some evidence of phytosynergy in some extracts of H. hemerocallidea and H. colchicifolia except for a few extracts which act as additive, autonomous and antagonistic when used to inhibit some bacterial and fungal strains. However, this was not the case for COX and AChE inhibition, as only acetone extracts acted in a synergistic way to reduce the activity of the enzyme. CONCLUSION: Even though the results give an indication of a positive interaction between some extracts of H. hemerocallidea and H. colchicifolia, the study was carried out on 1:1 v/v combinations only. It is therefore important to carry out isobologram studies, which considers more than one ratio of the combinations.

Hormone profiles in microalgae: gibberellins and brassinosteroids.

Endogenous gibberellins and brassinosteroids were quantified in 24 axenic microalgae strains from the Chlorophyceae, Trebouxiophyceae, Ulvophyceae and Charophyceae microalgae strains after 4 days in culture. This is the first report of endogenous gibberellins being successfully detected in microalgae. Between 18 and 20 gibberellins were quantified in all strains with concentrations ranging from 342.7 pg mg(-1) DW in Raphidocelis subcapitata MACC 317-4746.1 pg mg(-)(1) DW in Scotiellopsis terrestris MACC 44. Slower growing strains (S. terrestris MACC 44, Gyoerffyana humicola MACC 334, Nautococcus mamillatus MACC 716 and Chlorococcum ellipsoideum MACC 712) exhibited the highest gibberellin contents while lowest levels of gibberellins were found in faster growing strains (R. subcapitata MACC 317 and Coelastrum excentrica MACC 504). In all strains, the active gibberellin detected in the highest concentration was GA6, the predominant intermediates were GA15 and GA53 and the main biosynthetic end products were GA13 and GA51. Gibberellin profiles were similar in all strains except for the presence/absence of GA12 and GA12ald. To date this is the second report of endogenous brassinosteroids in microalgae. Brassinosteroids were detected in all 24 strains with concentrations ranging from 117.3 pg mg(-)(1) DW in R. subcapitata MACC 317-977.8 pg mg(-)(1) DW in Klebsormidium flaccidum MACC 692. Two brassinosteroids, brassinolide and castasterone were determined in all the strains. Generally, brassinolide occurred in higher concentrations than castasterone.

Antimicrobial, antioxidant, mutagenic and antimutagenic activities of Distephanus angulifolius and Ormocarpum trichocarpum.

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Distephanus angulifolius and Ormocarpum trichocarpum are used for treating stomach-related ailments in traditional medicine. AIMS OF THE STUDY: The present study evaluated the antibacterial, antioxidant, mutagenic and antimutagenic properties of extracts obtained from the leaves of Distephanus angulifolius and Ormocarpum trichocarpum. MATERIALS AND METHODS: The microtitre bioassay was used to determine the antibacterial activity against three Gram-positive and three Gram-negative bacteria. Antioxidant activity was determined using the free-radical scavenging and ß-carotene-linoleic acid model assays. The safety and possible protective properties of the extracts were investigated using Ames test. RESULTS: Dichloromethane fractions of both plants displayed a broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.16 to 0.63 mg/ml. A dose-dependent antioxidant activity was recorded in both plant species. All the evaluated samples showed no mutagenic as well as weak or no antimutagenic properties in the absence of exogenous metabolic activation. CONCLUSION: The results demonstrated the antibacterial and antioxidant activities of the leaves obtained from the two plant species. Furthermore, the data provides a rationale for the use of the plant species in treating stomach-related ailments in traditional medicine.

Antimicrobial and acetylcholinesterase inhibitory activities of Buddleja salviifolia (L.) Lam. leaf extracts and isolated compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Buddleja salviifolia leaves are used for the treatment of eye infections and neurodegenerative conditions by various tribes in South Africa. AIM OF STUDY: This study was designed to isolate the phenolic constituents from the leaf extracts of Buddleja salviifolia and evaluate their antimicrobial and acetylcholinesterase (AChE) activities. MATERIAL AND METHODS: Three phenolic compounds were isolated from the ethyl acetate fraction of a 20% aqueous methanol leaf extract of Buddleja salviifolia using Sephadex LH-20 and silica gel columns. Structure elucidation of the isolated compounds was carried out using spectroscopic techniques: mass spectrometry (ESI-TOF-MS) and NMR (1D and 2D). The extracts and isolated compounds were evaluated for antimicrobial and acetylcholinesterase activities using the microdilution technique. The bacteria used for the antimicrobial assays were Gram-positive Bacillus subtilis and Staphylococcus aureus and Gram-negative Escherichia coli and Klebsiella pneumoniae. RESULTS: The isolated compounds were characterized as: 4'-hydroxyphenyl ethyl vanillate (1) a new natural product, acteoside (2) and quercetin (3). The crude extract, fractions and the isolated compounds from the leaves of the plant exhibited a broad spectrum of antibacterial activity. The EtOAc fraction exhibited good activity against Bacillus subtilis and Staphylococcus aureus with MIC values ranging from 780.0 to 390.0 µg/mL. Isolated compound 2 exhibited good activity against Staphylococcus aureus with an MIC value of 62.5 µg/mL. The hexane and DCM fractions of leaves showed the best activity against Candida albicans with MIC and MFC values of 390.0 µg/mL. In the AChE inhibitory test, among the tested extracts, the hexane fraction was the most potent with an IC50 value of 107.4 µg/mL, whereas for the isolated compounds, it was compound (3) (quercetin) with an IC50 value of 66.8 µg/mL. CONCLUSIONS: Activities demonstrated by the extracts and isolated compounds support the ethnopharmacological use of Buddleja salviifolia against eye infections and neurodegenerative diseases.

Anti-inflammatory and mutagenic evaluation of medicinal plants used by Venda people against venereal and related diseases.

ETHNOPHARMACOLOGY RELEVANCE: Inflammation is a major risk factor for various human diseases including venereal diseases, often resulting in treatment complications. Plants have been traditionally used for treatment of many different diseases and have been successfully proven to be an alternative source in treatment of infectious diseases. AIM OF THE STUDY: This study was aimed at evaluating the anti-inflammatory activities and the mutagenic properties of 12 medicinal plants used by the Venda people against venereal and related diseases. MATERIALS AND METHODS: The plants were evaluated for their anti-inflammatory activity against the cyclooxygenase (COX-1 and -2) enzymes and genotoxicity using the Ames test, with and without S9 (metabolic activation) against Salmonella typhimurium tester strain TA98. RESULTS: DCM and PE extracts of Adansonia digitata bark, Bolusanthus speciosus bark, Pterocarpus angolensis bark and Pappea capensis leaves and EtOH and water extracts of Bolusanthus speciosus stem and Ekebergia capensis bark showed the best anti-inflammatory activity in both COX-1 and -2 assays at 250 µg/ml. These were further evaluated at three other concentrations (31.25, 62.5, and 125 µg/ml) to determine IC50 values. Water extracts of Ekebergia capensis bark showed the best IC50 value towards COX-1. The Ames test revealed that all plant extracts were non-mutagenic towards Salmonella typhimurium strain TA98 except for Elephantorrhiza burkei and Ekebergia capensis that showed weak mutagenicity. CONCLUSION: The active plants may offer a new source of chemicals for the effective treatment of anti-inflammatory conditions related to venereal diseases.