Medicinal plants used in managing diseases of the respiratory system among the Luo community: an appraisal of Kisumu East Sub-County, Kenya

Indigenous Knowledge and Quantitative Analysis of Medicinal Plants Used to Remedy Respiratory Tract Disorders in Mid-Western Tanzania

This study is aimed at documenting the indigenous knowledge and quantitative analysis of medicinal plants (MPs) used by traditional health practitioners (THPs) of Urambo District in mid-western Tanzania to manage respiratory tract disorders (RTDs). The ethnomedicinal data were collected using semistructured interviews with 55 THPs using a snowballing technique in the district. The data were analysed for indigenous knowledge among gender, age groups, education status, and experience. Family importance value (FIV), use value (UV), relative frequency of citation (RFC), informant consensus factor (ICF), and Jaccard index (JI) were computed. A total of 42 MPs representing 28 families were recorded being used against RTDs in the district. Fabaceae was the dominant family in terms of species (16.7%) and FIV (84%). Decoction (51.0%) was the preferred technique for preparing remedies, while trees (61.9%) and leaves (38.1%) were the most utilised life form and plant parts, respectively. The RFC in the current study varied from 0.055 (Musa paradisiaca L.) to 0.655 (Zingiber officinale Roscoe) and 0.073 (Dichrostachys cinerea (L.) Wight & Arn.) to 0.673 (Entada abyssinica Steud. ex A.Rich.), respectively. The highest ICF was recorded for cough (0.922). The JI ranged from 2.7 to 7.9. Among the documented MPs, 55% had least concern, 2% were endangered, 7% had data deficiency conservation status, and 36% had no record in the IUCN Red List. The study revealed that the district's population depends on MPs for healthcare. Thus, conservation strategies are needed for the sustainable utilisation of the MPs. Importantly, the documented MPs hold immense potential in future pharmacological and phytochemical studies, offering hope for the development of new drugs for RTDs. Also, the study suggests the need for scientific validation of the MP's efficacy and safety.

Antiasthmatic Medicinal Plants of Tanzania: An Ethnomedicinal and Ethnopharmacological Review

Traditional medicinal plants (TMPs) are a significant part of people's quality of life, offering a natural substitute for modern drugs with numerous side effects. In Tanzania, data on antiasthmatic TMPs are highly fragmented. This review, a comprehensive compilation of ethnobotanical research evidence, aimed to provide a thorough understanding of TMPs used by the locals for asthma management and identify species that have already been investigated in preclinical studies. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. To gather relevant literature on antiasthmatic TMPs used by Tanzanians, a web search using electronic databases (Scopus, PubMed, ProQuest, Academic Library, Web of Science, SciFinder, Wiley Online Library, Google Scholar, ScienceDirect, and African Journals Online) was conducted. The scientific names were verified through the Plants of the World Online database, and the collected information was analysed for descriptive statistics using Microsoft Excel software. The ethnomedicinal information was obtained from 24 different articles. Microsoft Excel software was used to analyse the data using descriptive statistics. A total of 62 TMPs belonging to 33 families were identified. Species of the Fabaceae (14.5%) and Rubiaceae families (8.1%) are the most utilized. The analysis revealed that trees (42.0%) and leaves (40.0%) are the most utilized life forms and plant parts, respectively. Most plant materials (59.7%) used to make remedies were collected from the wild environment. Decoction (55.0%) is the dominant preparation method of remedies, and the majority (69.0%) were orally administered. Of the recorded TMPs, 22.6% had their in vivo antiasthmatic activity reported in the literature. The review also highlighted the strategic significance of preparations of remedies made from TMPs for discovering and developing new antiasthmatic drugs. However, the need to identify the molecular targets of action and toxicological aspects of the TMPs should be considered.

Ethnobotanical study of medicinal plants used to treat human ailments in Quara district, northwestern Ethiopia

BACKGROUND

Ethiopia is recognized as one of the centers of origin for the diversity of many plant species, including medicinal plants. Throughout the country, a large proportion of the population relies on these therapeutic plant species for primary healthcare. While such traditional medicinal knowledge has been documented in some regions, there is a lack of information from the Quara district of northwestern Ethiopia. Therefore, this study aimed to document the indigenous and local knowledge of the use of medicinal plants among three ethnic groups residing in the area.

METHODOLOGY

An ethnobotanical study was conducted from August 2022 to October 2023 in ten kebeles of the Quara district. Data were collected through semi-structured interviews, field walks, and focus group discussions with 286 informants using snowball, purposive, and random sampling techniques. Quantitative analyses included Rahman's similarity index (RSI), informant consensus factor (ICF), and direct matrix ranking (DMR). Descriptive statistics were used to analyze basic ethnobotanical data.

RESULTS

A total of 128 medicinal plant species from 112 genera and 50 families were documented and used to treat 14 disease categories. There was a 28% overlap in medicinal plant knowledge among the three ethnic groups studied. Fabaceae was the most represented family with 22 species. Trees accounted for the majority of the documented plants (37.5%), and leaves were the most commonly used plant parts (23.1%). Oral administration (56.7%) of plant extracts was the primary mode of remedy preparation and use. The highest ICF value (0.93) was recorded for circulatory and blood-related disorders. The study identified nine plants and 39 therapeutic uses not previously reported in Ethiopia. The RSI showed high overlap with neighboring areas and low similarity with distant areas. Top-ranked multipurpose plants were Ziziphus spina-christi and Terminalia leiocarpa, with agricultural expansion and fuelwood collection identified as major threats.

CONCLUSION

The findings demonstrate the rich diversity of medicinal plants and associated traditional knowledge in the Quara district. The high ethnobotanical indices warrant further phytochemical and pharmacological investigations. Integrated conservation efforts are recommended to address the challenges facing these valuable plant resources.

Important Medicinal and Food Taxa (Orders and Families) in Kenya, Based on Three Quantitative Approaches

Globally, food and medicinal plants have been documented, but their use patterns are poorly understood. Useful plants are non-random subsets of flora, prioritizing certain taxa. This study evaluates orders and families prioritized for medicine and food in Kenya, using three statistical models: Regression, Binomial, and Bayesian approaches. An extensive literature search was conducted to gather information on indigenous flora, medicinal and food plants. Regression residuals, obtained using LlNEST linear regression function, were used to quantify if taxa had unexpectedly high number of useful species relative to the overall proportion in the flora. Bayesian analysis, performed using BETA.INV function, was used to obtain superior and inferior 95% probability credible intervals for the whole flora and for all taxa. To test for the significance of individual taxa departure from the expected number, binomial analysis using BINOMDIST function was performed to obtain p-values for all taxa. The three models identified 14 positive outlier medicinal orders, all with significant values (p < 0.05). Fabales had the highest (66.16) regression residuals, while Sapindales had the highest (1.1605) R-value. Thirty-eight positive outlier medicinal families were identified; 34 were significant outliers (p < 0.05). Rutaceae (1.6808) had the highest R-value, while Fabaceae had the highest regression residuals (63.2). Sixteen positive outlier food orders were recovered; 13 were significant outliers (p < 0.05). Gentianales (45.27) had the highest regression residuals, while Sapindales (2.3654) had the highest R-value. Forty-two positive outlier food families were recovered by the three models; 30 were significant outliers (p < 0.05). Anacardiaceae (5.163) had the highest R-value, while Fabaceae had the highest (28.72) regression residuals. This study presents important medicinal and food taxa in Kenya, and adds useful data for global comparisons.

Ethiopian Medicinal Plants Used for Respiratory Tract Disorders: Ethnomedicinal Review

Respiratory tract infections (RTIs) refer to infections in any part of the respiratory tract, which are common, with most of the world's population contracting at least one infection annually. These infections are becoming important causes of death and morbidity due to the rapid development of antimicrobial resistance that has resulted in reduced efficacy of existing drugs. Different local societies residing in Ethiopia have been reported to use traditional medicinal plants to treat RTIs. Nevertheless, up-to-date summarized data on the diversity of plants used in the traditional medicine system to treat RTIs in Ethiopia are lacking. The purpose of this review was to assess plant species used in traditional medicine to treat respiratory tract infections in Ethiopia. It attempts to compile available data required for undertaking further scientific investigations. The data were collected by searching for published scientific articles and other grey literature. Following this, medicinal plant (MP) diversity, growth forms, plant parts used, modes of remedy preparation and application, sources and distributions, and frequently treated respiratory disorders were examined. An Excel spreadsheet and SigmaPlot software were used to summarize and present the data. Two hundred twenty-nine (229) plant species that have been used to treat respiratory disorders in Ethiopia were documented. Lamiaceae was the most cited family (27 species), followed by Asteraceae (23 species), and Fabaceae (18 species), whereas cough was primarily cited as being treated by MPs and scored the highest frequency of citation (FOC = 243), followed by the common cold (FOC = 151) and asthma (FOC = 63). The top-cited plant species used in the treatment of RTIs were Eucalyptus globulus (6.8%), Allium sativum (5.5%), Zingiber officinale (4.2%), Ruta chalepensis (3.8%), and Ocimum lamiifolium (2.8%). Herbs were the dominant plant growth form (46%) used to treat respiratory diseases, and the most commonly used MP parts were leaves (37%). The leading traditional method used for preparation was decoction (25.5%), and the remedies were usually administered orally (64.6%). The MP origin reported was mainly from the wild (59%). High diversity of medicinal plants was reported as being used to treat various RTIs in Ethiopia. Information obtained from this review could be used as a reference for the selection of plants for further pharmacological, phytochemical, and toxicological investigations for their possible therapeutic applications and the development of new plant-based drugs.

Anti-respiratory syncytial virus and anti-herpes simplex virus activity of six Tanzanian medicinal plants with extended studies of Erythrina abyssinica stem bark

ETHNOPHARMACOLOGICAL RELEVANCE

Except for few highly pathogenic viruses, no antiviral drug has been approved for treatment of viral infections in humans. Plant extracts, selected based on their ethno-medical use, represent an important source of compounds for the development of novel candidate antiviral drugs. This especially concerns plants with ethnomedical records on their use in treatment of viral infections.

AIM OF THE STUDY

To identify and document medicinal plants used by traditional health practitioners (THPs) for treatment of respiratory infections and muco-cutaneous lesions in order to study their antiviral activity including identification of active components and elucidation of mode of antiviral activity.

MATERIALS AND METHODS

The ethno-medical survey was performed in the Kagera region of Tanzania. The THPs were asked for plants used for treatment of signs and symptoms of respiratory infections and watery muco-cutaneous blisters in oral and genital regions. The plants identified were successively extracted with n-hexane, ethyl acetate and water, and the extracts assayed for anti-respiratory syncytial virus (RSV), anti-herpes simplex virus 2 (HSV-2), and anti-human parainfluenza virus 2 (HPIV-2) activity in cultured cells. Antiviral components were separated by ethanol precipitation and CL-6B chromatography, and the mode of antiviral activity elucidated by the time-of-addition assay and selection for the virus variants resistant to antiviral plant extract.

RESULTS

THPs identified fifteen plants used for treatment of respiratory infections and muco-cutaneous blisters. The water extract, but not n-hexane or ethyl acetate extracts, of six of these plants including Erythrina abyssinica stem bark, inhibited infectivity of two glycosaminoglycan-binding viruses i.e., RSV and HSV-2 but not the sialic acid binding HPIV-2. An activity-guided separation revealed that antiviral component(s) of water extract of E. abyssinica could be precipitated with ethanol. This sample potently and selectively inhibited RSV and HSV-2 infectivity in cultured cells with IC50 values of 2.1 μg/ml (selectivity index >476) and 0.14 μg/ml (selectivity index >7143) respectively. The sample exhibited inhibitory effect on the virus attachment to and entry into the cells by directly targeting the viral particles. Indeed, 10 consecutive virus passages in HEp-2 cells in the presence of this extract selected for a resistant RSV variant lacking the attachment, viral membrane-associated, G protein due to a stop codon at amino acid residue 33 (Leu33stop). Fractionation of the E. abyssinica extract on a CL-6B column revealed that anti-RSV and HSV-2 activity correlated with carbohydrate content. The most pronounced antiviral activity was associated with a carbohydrate containing ingredient of molecular mass of <5 kDa, which may polymerize to antiviral composites of up to 410 kDa.

CONCLUSIONS

Altogether, the water extract of six medicinal plants showed anti-RSV and anti-HSV-2 activities. Extended studies of the stem bark of E. abyssinica identified antiviral components that potently and selectively inhibited infectivity of free RSV and HSV-2 particles, a feature of importance in topical treatment of these infections. This observation confirms ethno-medical information concerning the use of E. abyssinica extract for treatment of respiratory infections and herpetic lesions.

An Annotated Inventory of Tanzanian Medicinal Plants Traditionally Used for the Treatment of Respiratory Bacterial Infections

This review comprehensively covers and analyzes scientific information on plants used in Tanzanian traditional medicine against respiratory diseases. It covers ethnobotanical and ethnopharmacological information extracted from SciFinder, Google Scholar, and Reaxys as well as the literature collected at the Institute of Traditional Medicine in Dar-es-Salaam. Crude extracts and fractions of 133 plant species have literature reports on antimicrobial bioassays. Of these, 16 plant species had a minimum inhibitory activity of MIC ≤ 50 µg/mL. Structurally diverse compounds were reported for 49 plant species, of which 7 had constituents with MIC ≤ 5 µg/mL against various bacteria: Bryophyllum pinnatum (Lam.) Oken, Warburgia ugandensis Sprague, Diospyros mespiliformis Hochst. ex DC., Cassia abbreviata Oliv., Entada abyssinica A. Rich., Strychnos spinosa Lam., and Milicia excelsa (Welw.) C.C. Berg. The low number of antimicrobial active extracts and compounds suggests that antibacterial and antimycobacterial drug discovery needs to have a fresh look at ethnobotanical information, diverting from too reductionist an approach and better taking into account that the descriptions of symptoms and concepts of underlying diseases are different in traditional African and modern Western medicine. Nevertheless, some structurally diverse compounds found in anti-infective plants are highlighted in this review as worthy of detailed study and chemical modification.

Qualitative and quantitative phytochemical composition, antimicrobial activity, and brine shrimp cytotoxicity of different solvent extracts of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans

Background

The root, root bark, and root tubers of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans are used for managing bacterial and fungal infections among the Luo community of Kisumu East Sub County in Kenya. However, data on the efficacy of these plants against common bacterial and fungal pathogens is not available. The safety of these plants is also not known. This study aimed to investigate the phytochemical composition, antimicrobial properties, and safety of different solvent extracts of the roots, root barks, and root tubers of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans. The broth microdilution method evaluated the antimicrobial activities of the root, root bark, and root tuber extracts (water, acetone, and methanol) of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans. Gram-positive (Bacillus cereus, Staphylococcus aureus), gram-negative (Escherichia coli), and fungal (Candida albicans) microorganisms were used in the evaluation. The safety of the extracts was evaluated in Artemia salina. The phytochemical composition of the extracts was determined using qualitative and quantitative assays.

Results

In general, the extracts of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans displayed poor antimicrobial properties relative to conventional antimicrobial agents including Amoxicillin, Gentamicin, and Nystatin. The aqueous extract of Acanthus polystachyus and the aqueous, acetone, and methanol extracts of Keetia gueinzii were safe in Artemia salina but all other extracts were cytotoxic to Artemia salina.

Conclusions

These findings suggest that the use of the roots, root barks, and root tubers of Acanthus polystachyus, Keetia gueinzii, and Rhynchosia elegans is limited by poor antimicrobial efficacy and cytotoxicity.

Phytochemical Analysis and Investigation of the Antimicrobial and Cytotoxic Activities of Croton dichogamus Pax Crude Root Extracts

Background

Increasing antimicrobial resistance has led to an arduous search for new potent drugs from nature. In this search, plants have proved to be rich reservoirs of efficacious medicinal components that manage ailments. The current study is designed to investigate the phytochemical composition, antimicrobial activity, and the cytotoxicity of the crude root extracts of Croton dichogamus, a shrub that is commonly used in the eastern Africa for the management of infectious diseases.

Methods

The roots of Croton dichogamus were obtained, dried, ground, and extracted using three solvents (acetone, distilled water, and 50% ethanol). The antimicrobial activity was tested using agar well diffusion and microbroth dilution techniques against five human pathogens. The brine shrimp lethality assay was used to assess the toxic effect.

Results

The phytochemical screening indicated the presence of terpenoids, flavonoids, tannins, phenols, polyuronides, saponins, and anthracenes. The brine shrimp lethality assay indicated that all the extracts were highly cytotoxic with LC₅₀ values below 100 μg/ml. Acetonic extract had an LC₅₀ value of 4.148 μg/ml, hydroethanolic extract had 76.09 μg/ml, and aqueous extract had 42.61 μg/ml. All extracts showed the antibacterial activity against Gram-positive bacteria (B. cereus and S. aureus) and a fungal organism, C. albicans. The extracts showed no antibacterial effect on the Gram-negative bacterial strains (P. aeruginosa and E. coli) at a concentration of 250 mg/ml. The highest antimicrobial activity was demonstrated by the acetonic extract on B. cereus which had an MIC of 10.42 mg/ml and a zone of inhibition of 17.33 ± 0.58 at a concentration of 250 mg/ml.

Conclusion

In this research work, we report that C. dichogamus had the antimicrobial activity confirming the folklore claim. The results made a strong case for isolation of novel anticancer lead compounds.