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.

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.

Investigation into the genotoxicity of water extracts from Hypoxis species and a commercially available Hypoxis preparation.

We performed an in vitro evaluation of the genotoxic potential of water extracts from four Hypoxis species (Hypoxis hemerocallidea, H. colchicifolia, H. rigidula, H. acuminata) and a commercial preparation thereof using the neutral red uptake (NRU) assay, the alkaline comet assay and the cytome assay in human hepatoma HepG2 cells. The relative cytotoxicity of these samples was established by determining their NI50 values (50% inhibition of NRU), and these results were used for dose-finding in genotoxicity tests. None of the tested extracts were identified as genotoxic in both the alkaline comet assay and cytome assay.

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.

Antibacterial activity of flavonoids from the stem bark of Erythrina caffra thunb.

The antibacterial activity of the stem bark of Erythrina caffra Thunb. was investigated against different bacterial strains. The antibacterial activity was determined by a micro broth dilution assay. Antibacterial compounds were isolated and identified using a Bruker Avance III LPO NMR spectrometer. Four known flavonoids, abyssione-V 4'-O-methyl ether, 6,8-diprenylgenistein, alpinumisoflavone and burttinone, were isolated. All the compounds were active against both Gram-negative and Gram-positive bacteria. The minimum inhibitory concentration values obtained (MIC) ranged from 3.9 µg/mL to 125 µg/mL. This is the first report of antibacterial activity of burttinone and the isolation of these compounds from E. caffra.

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.

In vitro pharmacological evaluation of three Barleria species.

ETHNOPHARMACOLOGICAL RELEVANCE: Various parts of Barleria prionitis L. (Acanthaceae) are used in traditional medicine to treat infection-related ailments. A comparison of their activities and knowledge of their mechanisms of action are important for drug development and conservation. AIMS OF THE STUDY: This study investigated the antibacterial effects and underlying mechanisms of action of the anti-inflammatory activities of different parts of three Barleria species of South African origin. MATERIALS AND METHODS: Crude extracts of different parts of three Barleria species were investigated in vitro for their biological activity. Antibacterial activity was evaluated using the micro-dilution assay against two Gram-positive and two Gram-negative bacteria. Anti-inflammatory activity was evaluated using the cyclooxygenase COX-1 and COX-2 assays. RESULTS: All the extracts showed broad-spectrum antibacterial activity with minimum inhibitory concentrations ranging from 0.059 to 6.25mg/ml. Twelve out of 21 crude extracts evaluated showed good activity (>70%) in the COX-1 assay while 10 extracts showed good activity in the COX-2 assay. All the petroleum ether extracts (except B. prionitis stem) exhibited good inhibition of prostaglandin synthesis in COX-1. CONCLUSION: The results demonstrated the therapeutic potential of these plants as antibacterial and anti-inflammatory agents. Their anti-inflammatory properties are mediated by the inhibition of the cyclooxygenase enzymes.

Mutagenic and antimutagenic properties of extracts from South African traditional medicinal plants.

AIM OF THE STUDY: The aim of this paper was to summarize the results of our investigations on the in vitro genotoxic as well as antigenotoxic effects of a great number of selected South African traditional medicinal plants. MATERIALS AND METHODS: Investigations of methanol and dichloromethane extracts of selected plants were conducted with the bacterial Ames, Umu-C and VITOTOX tests, and with the cytochalasin B micronucleus test and alkaline comet assay in human white blood cells. RESULTS: A number of extracts were found to have genotoxic properties. Amongst the genotoxic plant extracts, especially methanol extracts of Helichrysum simillimum DC. (Asteraceae) should be highlighted. On the other hand, some plant extracts also showed antimutagenic potential. Here Bauhinia galpinii N.E.Br. (Fabaceae) and especially Chlerodendrum myricoides (Hochst.) Vatke (=Rotheca myricoides (Hochst.) Steane & Mabb.; Lamiaceae) appear to have antimutagenic properties. CONCLUSION: The safe use of Helichrysum similimum should be questioned and further investigations on its mutagenicity and overall biological properties should be encouraged. Antimutagenic properties of especially Bauhinia galpinii and Rotheca myricoides are considered of particular interest as it may be assumed that these antimutagenic natural substances are able to lower the cancer risk from everyday exposures to environmental mutagens as well as to mutagenic pharmaceuticals.

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.

Antimicrobial activity of South African Podocarpus species.

ETHNOPHARMACOLOGICAL RELEVANCE: Several species of Podocarpus (Podocarpaceae) are utilized in treating ailments across the world. In Africa, four species are used traditionally in both animal and human health. AIM OF THE STUDY: To investigate the antimicrobial activity of Podocarpus species against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Candida albicans. MATERIALS AND METHODS: Six solvents of varying polarity were used for extraction. Antibacterial activity was assessed using the microdilution bioassay and for antifungal activity, the microdilution bioassay and (M27-P) broth dilution were used. RESULTS: All species exhibited antimicrobial activity with MIC values of less than 1mg/ml. Inhibition against Gram-positive bacteria was stronger with an MIC value of 98 microg/ml while for Gram-negative bacteria, the highest inhibition was against Klebsiella pneumoniae with an MIC value of 0.33 mg/ml. All species exhibited strong antifungal activity with the best MIC being 30 microg/ml after 48 h. CONCLUSIONS: All four species exhibited strong inhibition against all tested microbials, based on Aligiannis et al. [Aligiannis, N., Kalpotzakis, E., Mitaku, S., Chinou, I.B., 2001. Composition and antimicrobial activity of the essential oils of two Origanum species. Journal of Agricultural and Food Chemistry 40, 4168-4170] classification they can be classified as strong inhibitors.

Kaempferol, a mutagenic flavonol from Helichrysum simillimum.

Helichrysum simillimum is native to South Africa. It is used for the treatment of coughs, colds, fever, infections, headache, and menstrual pain. Extracts of this species showed mutagenic effects in the Salmonella/microsome assay. The aim of this study was to isolate and determine the mutagenic constituents of H. simillimum. Bioassay-guided fractionation of 90% aqueous methanol extracts, using Salmonella typhimurium TA98, led to the isolation of the flavonol kaempferol.

Production of radioactive quality assurance phantoms using a standard inkjet printer.

This note proposes the use of a standard inkjet printer to produce radioactive (99m)Tc phantoms that can be used for routine quality control of gamma cameras. The amount of activity that will be deposited on paper per unit area was predicted and compared to the measured activity. The uniformity of the printouts was compared to the uniformity obtained with a standard (57)Co flood source. A scintillation detector connected to a multi-channel analyzer was used to evaluate the uniformity of the printout independently from the gamma camera. Joining two A4 size printed phantoms to create larger sources was evaluated. The spatial resolution obtained with printed sources was compared to that obtained using standard line source techniques. The results indicated that the uniformity of the printed phantoms compared well with those obtained with the (57)Co flood source (integral uniformity 2.29% (printed source) and 2.10% ((57)Co flood source)). There was no difference in the resolution measurements obtained with the printed sources and those obtained with the standard methods. This study demonstrates that affordable phantoms can easily be created to evaluate system uniformity and resolution in any department where a standard PC and inkjet printer are available.

Effects of autoclaving and charcoal on root-promoting substances present in water extracts made from gelling agents.

The root-promoting ability of water extracts made from gelling agents (agar and Gelrite) was investigated using the mungbean rooting bioassay. Autoclaving these water extracts decreased the number of roots in mungbean cuttings compared to the controls. The addition of activated charcoal to the water extracts from Agar Bacteriological and Agar Commercial Gel had no effect on their root-promoting ability. Extracts with exogenous indole-3-butyric acid (IBA) which were treated by autoclaving or via a freeze-thaw cycle, significantly increased rooting. However, incorporation of activated charcoal to similar IBA-containing extracts reduced rooting. Our results indicate that more attention should be given to the choice of gelling agent and its interaction with other additives in the media used during tissue culture.

Antibacterial and antifungal activity of traditional medicinal plants used against venereal diseases in South Africa.

Aqueous, ethanolic and ethyl acetate extracts of 13 plants used in South Africa for the treatment of venereal diseases were screened for antibacterial and antifungal activity. Among the plants tested, Gunnera perpensa, Harpephyllum caffrum, Hypoxis latifolia and Ledebouria ovatifolia showed the best antibacterial activity. The aqueous extracts of Gunnera perpensa and Harpephyllum caffrum were most active against all the tested bacteria. In antifungal screening, good activity was shown by the ethanolic extracts of Bersama lucens and Harpephyllum caffrum. Only in the case of Harpephyllum caffrum did aqueous extracts have activity against Candida albicans.

Studies on antibacterial, anti-inflammatory and antioxidant activity of herbal remedies used in the treatment of benign prostatic hyperplasia and prostatitis.

Crude water and ethanolic extracts of five herbal remedies reported in the literature for traditional treatment of benign prostatic hyperplasia (BPH) and/or prostatitis were investigated for their effect on hydroxyl scavenging activity, antibacterial activity and their ability to inhibit cyclooxygenase-1 and -2 (COX-1 and COX-2) catalysed prostaglandin biosynthesis. Both the water and ethanol extracts of Hypoxis hemerocallidea and Epilobium parviflorum inhibited the growth of Escherichia coli. All 10 extracts scavenged the hydroxyl radical but with various potencies (32-93%). Ethanolic extracts were the most active in inhibiting COX-1 catalysed prostaglandin biosynthesis. The ethanolic extract of Epilobium parviflorum showed inhibitory effects on both the COX-1 and -2 catalysed prostaglandin biosynthesis, inhibited growth of Escherichia coli and exerted antioxidant activity. Although these results support the traditional use of Epilobium parviflorum for treatment of prostatitis and BPH, further investigation is required, for this promising plant.

Evaluation of the mutagenic and antimutagenic effects of South African plants.

Dichloromethane and 90% methanol extracts of 42 South African plants were screened for mutagenicity and antimutagenicity using the Salmonella/microsome mutagenicity assay (Ames) against Salmonella typhimurium TA98 and TA100 bacterial strains in the presence and absence of metabolic activator S9. The methanol extracts from whole plants of Helichrysum simillimum, Helichrysum herbaceum and Helichrysum rugulosum indicated mutagenicity. These are the first reported tests on the mutagenicity of Helichrysum species. Six species indicated antimutagenic properties, all in the presence of S9: methanol leaf extract of Bauhinia galpinii, and dichloromethane leaf extracts of Bauhinia galpinii, Clerodendrum myricoides, Datura stramonium, Buddleja saligna, Millettia sutherlandii and Sutherlandia frutescens.

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.