Heteropyxis Natalensis Research Articles

The effect of a poly-herbal plant extract on the adhesion of Streptococcus mutans to tooth enamel

BackgroundDental caries, also known as tooth decay or cavity formation, is one of the world’s most widespread dental conditions. It is a plaque-related infection caused mainly by Streptococcus mutans. People have relied on several plant species to treat oral infections; Heteropyxis natalensis, for example, has been used to treat toothache and gum infections.MethodsIn this study, the antimicrobial and anti-adherence properties of H. natalensis and Camellia sinensis, as well as tea tree and peppermint essential oils were investigated on tooth enamel.ResultsThe bacterial load of S. mutans was reduced by approximately two orders of a magnitude after 48 h, with a lesser extent on the commensal bacteria, Lactobacillus paracasei. Scanning electron micrographs of enamel blocks showed a reduction in the attachment and chain formation of S. mutans and degraded cell morphology. Lastly, the combination and each component individually, showed low to no cellular toxicity when tested on human macrophages.ConclusionsThis is the first report of this polyherbal regarding its selectivity and potential prevention of dental caries.

Green synthesis of silver nanoparticles from Heteropyxis natalensis leaf extract and their potential antibacterial efficacy

Green synthesis of silver nanoparticles from Heteropyxis natalensis leaf extract and their potential antibacterial efficacy

Foliar microstructure and histochemical analysis of the lavender tree (Heteropyxis natalensis Harv.)

Heteropyxis natalensis Harv. is a native South African tree used in traditional medicine among Venda and Zulu communities. In this study, micromorphological investigations using light and scanning electron microscopy identified long, tapered non-glandular trichomes on the abaxial and adaxial surfaces of the leaves. The total number of trichomes appeared to be greater on emergent leaves and decreased as leaves matured. In addition, schizolysigenous secretory cavities and druse crystals were found within the leaves. Swollen subdermal secretory cavities were also distributed in the midrib of the leaves. Transmission electron microscopy confirmed the presence of nuclei, plastids, mitochondria, vesicles, rough endoplasmic reticulum cisternae and Golgi bodies in the secretory epithelia of these cavities. Various histochemical tests revealed the presence of alkaloids, phenolics, lipids, proteins, essential oils, resin acids and trace amounts of unesterified pectins and polysaccharides in the leaves. This study provides new findings and contributes to the existing research regarding H. natalensis with respect to the micromorphology, ultrastructure and histochemical composition of this species.

PHYTOCHEMICAL AND ETHNOPHARMACOLOGICAL REVIEW OF HETEROPYXIS NATALENSIS

The bark, leaves, roots, and twigs of Heteropyxis natalensis are widely used as herbal medicines in Southern Africa. The aim of this study was to review the phytochemical and ethnopharmacological properties of H. natalensis so as to provide baseline data required for evaluating the therapeutic potential of the species. Information on the botanical profile, medicinal uses, phytochemistry, and pharmacological properties of H. natalensis was undertaken using databases such as ScienceDirect, SciFinder, PubMed, Google Scholar, Medline, SCOPUS, EThOS, ProQuest, OATD, and open-thesis. Pre-electronic literature of conference papers, scientific articles, books, book chapters, dissertations, and theses were carried out at the university library. Literature search revealed that H. natalensis is used as an aphrodisiac, anti-infection, blood purifier, decongestant, for weaning, ethnoveterinary medicine and as herbal medicine for bleeding disorders, gums, nose, colds, gum infections, impotence, menorrhagia, respiratory disorders, toothache, and wounds. Phytochemical compounds identified from the species include essential oils, 3β-hydroxylup-20(29)-en-28-al, (E)-1-(2’,4’-dihyroxy,5’- methoxy,3’-methylphenyl)-3-phenylprop-2-en-1-one, (2E)-2-[(2E)-1-hydroxy-3-phenylprop-2-en-1-ylidene]-5-methoxy-6,6-dimethylcyclohex-4-ene- 1,3-dione, 2’,4’-dihydroxy-6’-methoxy-3’,5’-dimethylchalcone, 3’,4’,5’-tri-O-methyl-3,4-methylenedioxy ellagic acid, 3,5,7-trihydroxyflavan, 5-hydroxy- 7-methoxy-6-methylflavanone, aurentiacin A, betulinic acid, cardamomin, lupenone, lupeol, quercetin, and sitost-4-en-3-one. Pharmacological studies revealed that H. natalensis extracts and compounds have antibacterial, antimycobacterial, antifungal, antioxidant, anti-inflammatory, cytotoxicity, and pro-inflammatory activities. Detailed studies are required to establish the efficacy, clinical relevance, safety and mechanisms of action of the plant extracts, and compounds of H. natalensis.

Novel Cryphonectriaceae from La Réunion and South Africa, and their pathogenicity on Eucalyptus

Fungi in the Cryphonectriaceae are important canker pathogens of plants in the Melastomataceae and Myrtaceae (Myrtales). These fungi are known to undergo host jumps or shifts. In this study, fruiting structures resembling those of Cryphonectriaceae were collected and isolated from dying branches of Syzygium cordatum and root collars of Heteropyxis natalensis in South Africa, and from cankers on the bark of Tibouchina grandifolia in La Reunion. A phylogenetic species concept was used to identify the fungi using partial sequences of the large subunit and internal transcribed spacer regions of the nuclear ribosomal DNA, and two regions of the β-tubulin gene. The results revealed a new genus and species in the Cryphonectriaceae from South Africa that is provided with the name Myrtonectria myrtacearum gen. et sp. nov. Two new species of Celoporthe (Cel.) were recognised from La Reunion and these are described as Cel. borbonica sp. nov. and Cel. tibouchinae sp. nov. The new taxa were mildly pathogenic in pathogenicity tests on a clone of Eucalyptus grandis. Similar to other related taxa in the Cryphonectriaceae, they appear to be endophytes and latent pathogens that could threaten Eucalyptus forestry in the future.

Biological Activities of Heteropyxis natalensis Against Micro-Organisms Involved in Oral Infections.

The use of complementary and alternative medicine from plants in South Africa, as in the rest of the world, continues to increase. Heteropyxis natalensis, known as the Lavender tree, is indigenous to South Africa and is traditionally used for oral care. The ethanolic extract, of the leaves and twigs, of H. natalensis was investigated for antimicrobial activity against selected oral microorganisms. Actinomyces israelii was found to be the most sensitive oral microorganism to the extract, with a minimum inhibitory concentration (MIC) of 0.88 mg/ml and an MIC of 2.6 mg/ml against Streptococcus mutans. Five known compounds were identified from the ethanolic extract of H. natalensis. The compounds were identified as aurentiacin A (1), cardamomin (2), 5-hydroxy-7-methoxy-6-methylflavanone (3), quercetin (4) and 3,5,7-trihydroxyflavan (5). The MICs of the compounds 1 and 4 were found to be 0.06 mg/ml and 1 mg/ml, respectively, against A. israelii. The cytotoxicity, acute and sub-acute toxicity in pre-clinical studies were also determined for H. natalensis. The extract showed moderate cytotoxicity (35.56 ± 0.16 μg/ml) on human monocyte cells. The acute and sub-acute toxicity analysis of H. natalensis indicated the NOEL (no-observed-effect level) at 200 mg/kg. Interleukin-8 (IL-8) is a chemokine that stimulates the recruitment of leukocytes. A significant reduction of IL-8 production by macrophage cells was observed when exposed to the extract of H. natalensis. It is possible that H. natalensis can prevent excessive tissue damage in periodontal diseases through its reduction of inflammation. Enzymatic bioanalysis of lactic and acetic acid production from Streptococcus mutans and Lactobacillus paracasei was done. A reduction in the acid production from each bacterium was observed on exposure to the extract of H. natalensis. Consequently, this increased the pH, which could possibly reduce the demineralization of enamel which may help prevent the formation of dental caries. In addition the extract may be considered for preventing periodontal diseases.

Antimycobacterial activity against different pathogens and selectivity index of fourteen medicinal plants used in southern Africa to treat tuberculosis and respiratory ailments

Many plants are used in traditional medicine to treat tuberculosis and other respiratory disorders in Africa. The emergence of multiple drug resistance has become a major threat and thus calls for an urgent need to search for new effective and safe anti-TB agents. The aim was to determine the antimycobacterial activity and the safety of the acetone leaf extracts of 14 plant species used in southern Africa to treat tuberculosis and pulmonary ailments.The antimycobacterial activity was evaluated by a tetrazolium violet based broth microdilution method against three fast-growing mycobacteria species (Mycobacterium smegmatis, Mycobacterium aurum and M. fortuitum) and one pathogenic M. tuberculosis field strain. The in vitro cellular toxicity was determined using the MTT assay on Vero monkey kidney cells. The extraction yield, the LC50 and MIC values were used to determine the total activity (TA) and the selectivity index (SI) of the extracts.Extracts had moderate to weak activity with the MIC values ranging from 0.039 to >2.5mg/mL. M. fortuitum appeared to be better predictor of activity against pathogenic M. tuberculosis than M. smegmatis and M. aurum. Extracts from Heteropyxis natalensis (3.3) and Hexalobus monopetalus (2.47) had the highest selectivity index.The results substantiate the safety and in some cases the potential efficacy of the traditional use of these species against tuberculosis and pulmonary ailments.

Predicting the influence of multiple components on microbial inhibition using a logistic response model--a novel approach.

BackgroundThere are several synergistic methods available. However, there is a vast discrepancy in the interpretation of the synergistic results. Also, these synergistic methods do not assess the influence the tested components (drugs, plant and natural extracts), have upon one another, when more than two components are combined.MethodsA modified checkerboard method was used to evaluate the synergistic potential of Heteropyxis natalensis, Melaleuca alternifolia, Mentha piperita and the green tea extract known as TEAVIGO™. The synergistic combination was tested against the oral pathogens, Streptococcus mutans, Prevotella intermedia and Candida albicans. Inhibition data obtained from the checkerboard method, in the form of binary code, was used to compute a logistic response model with statistically significant results (p < 0.05). This information was used to construct a novel predictive inhibition model.ResultsBased on the predictive inhibition model for each microorganism, the oral pathogens tested were successfully inhibited (at 100% probability) with their respective synergistic combinations. The predictive inhibition model also provided information on the influence that different components have upon one another, and on the overall probability of inhibition.ConclusionsUsing the logistic response model negates the need to ‘calculate’ synergism as the results are statistically significant. In successfully determining the influence multiple components have upon one another and their effect on microbial inhibition, a novel predictive model was established. This ability to screen multiple components may have far reaching effects in ethnopharmacology, agriculture and pharmaceuticals.

Morphological and Molecular Evidence of Polyphyly in Rhodomyrtus (Myrtaceae: Myrteae)

Abstract The monophyly of the genus Rhodomyrtus (Myrtaceae) was tested using data from morphology and the nuclear ribosomal ITS regions (ITS-1, ITS-2) and 5.8S gene. Representative species from baccate genera hypothesized to be closely related to Rhodomyrtus were included, such as Archirhodomyrtus, Octamyrtus, Knnakomyrtus, and some genera believed to be more distantly related, including Rhodamnia, Decaspermum, Pilidiostigma, and Myrtastrum. Up to four capsular-fruited outgroup species were used to root the trees (Heteropyxis natalensis, Carpolepis tardiflora, Lophostemon confertus, and Metrosideros rotundifolia). Morphological data using neighbor joining scattered species of Rhodomyrtus across several branches but generally recovered genera other than Rhodomyrtus. Using parsimony, the morphological data analysis also rejected the monophyly of Rhodomyrtus and resulted in consensus trees with relatively low resolution and bootstrap support. Based on traditionally recognized generic boundaries, results from...

The proposed colonisation sequence of woody species in the Sourish Mixed Bushveld of the Limpopo province, South Africa

The long-term establishment sequence of the woody component of the Sourish Mixed Bushveld of the Limpopo province was studied and documented. Vegetation surveys were conducted at a protected site at the Towoomba Agricultural Development Centre during 1977 and 2000. Over the 23-year period, bush density at the site increased by 33%. Changes in the woody component indicated a shift from an acacia-dominated site to one dominated by broadleaved tree species. Early colonisers included mostly Acacia species (A. karroo, A. robusta, A. nilotica, A. gerrardii, A. tortilis, A. caffra, A. habeclada and A. mellifera), Dichrostachys cinerea and a few broadleaved species (Ximenia caffra, Dombeya rotundifolia and Searsia spp.). Intermediate colonisers included various shrubs (Diospyros lycioides, the Maytenus/Gymnosporia species group, Euclea species, Carissa bispinosa and Grewia spp.), a limited number of tree species (Pappea capensis, Boscia albitrunca and Ziziphus mucronata) and only two legumes (A. robusta and Peltophorum africanum). Late colonisers included only broadleaved shrubs and Waterberg Mountain Sourveld tree species (Grewia flavescens, Tarchonanthus camphoratus, Berchemia zeyerii, Cassine transvaalensis, Schotia brachypetala, Ximenia caffra, Heteropyxis natalensis, Terminalia sericea, Vangueria infausta and Searsia lancea). The leguminous and broadleaved components appeared to have distinct establishment sequences. Acacia spp. appeared to facilitate the early invasion of broadleaved woody species.

Isolation and characterization of a new chalcone from the leaves of Heteropyxis natalensis

Chromatographic analysis of the defatted dichloromethane extract of the leaves ofHeteropyxis natalensis afforded the isolation of (E)-1-(2’,4’-dihydroxy, 5’-methoxy, 3’-methylphenyl)-3-phenylprop-2-en-1-one (R1 = Me; R2 = OH; R3 = OMe; R4 = H) a chalcone. The structure of this compound was established by its spectroscopic data-1D, 2D-NMR, EIMS and HR-EIMS. Key words: Chalcones, Heteropyxis natalensis, heteropyxidaceae, flavone

Validation of smoke inhalation therapy to treat microbial infections

Aim of the study In traditional healing, the burning of selected indigenous medicinal plants and the inhalation of the liberated smoke are widely accepted and a practiced route of administration. This study elucidated the rationale behind this commonly practiced treatment by examining the antimicrobial activity for five indigenous South African medicinal plants commonly administered through inhalation ( Artemisia afra, Heteropyxis natalensis, Myrothamnus flabellifolius, Pellaea calomelanos and Tarchonanthus camphoratus). Material and Methods An apparatus was designed to simulate the burning process that occurs in a traditional setting and the smoke fraction was captured for analysis and bioassay. Methanol and acetone extracts as well as the essential oil (for the aromatic species) were prepared and assayed in parallel with the smoke fraction. Results Antimicrobial data revealed that in most cases, the ‘smoke-extract’ obtained after burning had lower minimum inhibitory concentration (MIC) values than the corresponding solvent extracts and essential oils. The combustion, acetone and methanol extracts produced different chromatographic profiles as demonstrated for Pellaea calomelanos where several compounds noted in the smoke fraction were not present in the other extracts. Conclusion These results suggest that the combustion process produces an ‘extract’ with superior antimicrobial activity and provides in vitro evidence for inhalation of medicinal smoke as an efficient mode of administration in traditional healing.

Seasonal and geographical variation of Heteropyxis natalensis essential oil and the effect thereof on the antimicrobial activity

Heteropyxis natalensis (Heteropyxidaceae) is traditionally used to treat respiratory disorders, and as a decongestant and antimicrobial agent. The seasonal variation of the hydrodistilled essential oil was investigated. Three trees in the Johannesburg Botanical Garden (Gauteng) indicated similar chemical profiles with fluctuation in the levels of the two major constituents (1,8-cineole and limonene). Little variation between the antimicrobial activity of seasonally collected samples was documented, with standard deviations of ± 0.3 to ± 3.3 depending on the pathogen studied. Moderate antimicrobial activity (3.0–16.0 mg/ml) was noted for most pathogens tested with Cryptococcus neoformans exhibiting the highest sensitivity (2.0–3.0 mg/ml). The chemogeographical variation of the oil composition from five of the seven distinct localities studied all contains 1,8-cineole and limonene as major constituents. The antimicrobial study of these samples indicated little variability between localities (standard deviation of ± 0.5 to ± 3.8). As observed in the seasonal variation study, C. neoformans displayed the highest sensitivity (0.5–2.0 mg/ml). One oil sample (Lagalametse), was distinctly different both chemically and microbiologically.

Total phenolic content and antioxidant activity in selected medicinal plants of Zimbabwe

SummarySeven commonly known medicinal plants from Zimbabwe were analysed for their antioxidant activity as well as their total phenolic content. The plant samples used in this study were Albizia amara, Elionurus muticus, Heteropyxis natalensis, Hoslundia opposita, Lippia javanica, Ocimum urticifolia and Warburgia salutaris. The plant samples were extracted using 70% ethanol. The 2,2‐diphenyl‐1‐picrylhydrazyl radical assay was used to determine the antioxidant activity of the plant extracts, while the Folin–Ciocalteu method was used to determine the total phenolic content. The antioxidant activities of the plant extracts ranged from 95.84 ± 0.50% for E. muticus to 5.31 ± 4.47% for H. opposita. Total phenolics in the plant extract estimated as tannic acid equivalent (TAE) ranged from 0.098 ± 0.005 mg per 100 g for H. natalensis to 0.024 ± 0.006 TAE for H. opposita. There was a poor correlation (R = 0.522) between total phenolic content and antioxidant activity in the plant samples. The results indicate the presence of phenolic compounds as well as significant antioxidant activity.

A Comparative Investigation of the Antimicrobial Properties of Indigenous South African Aromatic Plants with Popular Commercially Available Essential Oils

Essential oils have been accepted and recognized as having several therapeutic applications. Popular commercial oils such its lavender, rosemary, tea tree, thyme and peppermint have been used extensively in aromatherapy and as a treatment regimen against bacterial and fungal infections. Extensive studies on indigenous essential oils used in South African traditional healing rites indicate efficacy against a number of pathogens. By means of comparatively determining the MIC of the above-mentioned popular commercial oils against the essential oils of five indigenous plants (Myrothamnus flabellifolius, Osmitopsis asteriscoides, Heteropyxis natalensis, Artemisia afra and Lippiajavanica), efficacy was determined against eight bacterial reference strains and two yeast reference strains. The laboratory conditions and inoculum were standardized to ensure all 10 essential oils (commercial and indigenous) were evaluated under identical conditions. Where MIC data indicated coinciding values between commercial and indigenous oils, the MIC was further refined to narrow the increments. To comparatively demonstrate the time kill efficacy, commercial and indigenous oils were exposed to Staphylococcus aureus, Klebsiella pneumoniae and Candida albicans and the cidal efficacy plotted over time against the logarithm of viable colonies. Results indicate that South African indigenous essential oils compare favorably with commercial oils studied herein. Of all oils studied, Myrothamnus flabellifolius showed the most rapid cidal effect against all three pathogens tested.

In Vitro 5-Lipoxygenase Activity of Three Indigenous South African Aromatic Plants Used in Traditional Healing and the Stereospecific Activity of Limonene in the 5-Lipoxygenase Assay

An investigation was undertaken to determine the 5-lipoxygenase inhibitory activity of aromatic plants traditionally used to treat dermatological pathologies. Guided by ethnobotanical literature and availability from natural sources, the essential oils of Helichrysum odoratissimum (L.) Less., Heteropyxis natalensis Harv. and Lippia javanica (Burm. f.) Spreng, were collected. The hydrodistilled essential oils displayed promising 5-lipoxygenase inhibitory activity with IC50 values between 35 and 75 ppm. The oil compositions were determined by GC and GC/MS. Major compounds possibly contributing to the anti-inflammatory activity include β-caryophyllene, 1,8-cineole and limonene. Enantiomers and racemic mixtures of limonene displayed significantly different 5-lipoxygenase inhibitory activity suggesting stereoselectivity of the enzyme-catalyzed reaction. Furthermore, the monoterpene 1,8-cineole appeared to cause partial potentiation of the anti-inflammatory activity displayed by limonene.

Heteropyxis natalensis, a new host ofPuccinia psidiirust

Artificial inoculation tests have shown that Heteropyxis natalensis is a new host of the Eucalyptus rust fungus Puccinia psidii. This tree resides in the Heteropyxidaceae, a southern African family, and it is the first species outside the Myrtaceae shown to be susceptible to P. psidii. H. natalensis was highly susceptible to infection by the rust and would be severely damaged if the pathogen were accidentally introduced into Southern Africa.

Essential Oils of Cultivated Heteropyxis natalensis (Harv.) and Cultivated Heteromorpha trifoliata (Wendl.) Eckl. & Zey. from Zimbabwe

The plant material from organically cultivated Heteropyxis natalensis (Harv.) and cultivated Heteromorpha trifoliata (Wendl.) Eckl. & Zey., from Zimbabwe were steam distilled for essential oils and their composition compared with those from wild plants. The major components in the oil from the summer of semi-dry cultivated H. natalensis were: 1,8-cineole (20.7–32.1%), linalool (21.7–26.8%), limonene (13.1–16.5%), myrcene (3.7–9.3%) and (Z)-β-ocimene (2.3–12.4%). The wild plant had linalool (26.5%), 1,8-cineole (24.7%) and limonene (13.3%) as major components in the summer and 1,8-cineole (37.2%) and limonene (22.1%) as major components in the winter/dry season. The oil from the fresh cultivated H. trifoliata had sabinene (15.7–30.0%), limonene (9.5–15.7%) and (Z)-β-ocimene (7.1–12.2%), myrcene (8.5–11.1%) and δ-3-carene (3.6–10.1%) as major components. The oil from the wild semi-dry herb had limonene (15.4%) and sabinene (13.7%) as the main components. The cultivation of indigenous medicinal plants is intended to promote their rational use and conservation.

The essential oil from Heteropyxis natalensis harv: Its antimicrobial activities and phytoconstituents

AbstractThe essential oil obtained from Heteropyxis natalensis by steam distillation was tested for antimicrobial properties. Twenty five bacterial and four fungal species were used as test organisms in this study. These included animal and plant pathogens, food poisoning bacteria and mycotoxigenic fungal strains. The essential oil exhibited considerable inhibitory activities against all the test organisms. GC–MS analysis indicated the essential oil contained 1,8‐cineole, limonene, β‐myrcene, α‐phellandrene and α‐pinene.

Constituents of the Essential Oil ofHeteropyxis natalensis

ABSTRACT The essential oil of Heteropyxis natalensis Harv. (“lavender tree,” family Heteropyxidaceae) from Zimbabwe was analyzed and found to contain more than 90% of monoterpenes (hydrocarbons and oxygenated compounds). The composition is strongly dependent on the season. The oil produced in the summer contained (E)-β-ocimene (29%), linalool (25%), myrcene (8.5%), 1, 8-cineole (9.5%), p-mentha-1(7), 8-diene (6%) and limonene (6%), whereas the oil produced in the winter was richer in 1, 8-cineole (40%) and limonene (21%), lower in (E)-β-ocimene (6%), myrcene (4%) and p-mentha-1(7), 8-diene (1.5%), and very low in linalool (1%).