Antimicrobial Activity and Probable Mechanisms of Action of Medicinal Plants of Kenya: Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus

Mwitari, Peter; Ayeka, Peter Amwoga; Ondicho, Joyce; Matu, Esther N.; Bii, Christine

doi:10.1371/journal.pone.0065619

Cited by 96 publications

(64 citation statements)

References 19 publications

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“…The procedure was repeated using plant extracts at 1.0 g/ml in place of SIRE. The general antimicrobial activity using Escherichia coli (ATCC 2592), Staphylococcus aureus (ATCC 25923) and Candida albican (ATCC 90028) was assayed by standard disc diffusion method according to Ayo et al (2007), Mbaveng et al (2008), Ngoci et al (2012) and Mwitari et al (2013).…”

Section: Antitubercular and Antimicrobial Activity Screeningmentioning

confidence: 99%

Potency of extracts of selected plant species from Mbeere, Embu County-Kenya against Mycobacterium tuberculosis

Njeru¹,

Obonyo²

2016

J. Med. Plants Res.

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Tuberculosis is a serious chronic infectious disease affecting large global population. While efforts to control tuberculosis have intensified, they are challenged by rapid drug resistance development. For this reason, prospecting for compounds with potential antituberculous activity have been stepped up. The current study was done in a participatory appraisal manner to identify ten plants commonly used for management of "persistent coughs". Bioassays were conducted against Mycobacterium tuberculosis (H37Rv ATCC 27294) using the BACTEC MGIT ™ 960 system. This was followed by assay of toxicity of the extracts towards Vero cells (ATCC CCL-81). Six extracts showed remarkable antitubercular activity. Four extracts had complete inhibition (0 GU-Growth Units) of Mycobacterium tuberculosis. The extracts were tested for their general antimicrobial activity and found to be broad spectrum antimicrobials. The highest activity against Escherichia coli (15.3 mm) was by Cissampelos pareira, while Mangifera indica yielded the highest activity against Staphylococcus aureus (11.7 mm) and Candida albicans (12.0 mm). In addition, six crude methanolic extracts were found to be within the acceptable toxicity limit (CC 50 <90 µg/ml). The observed activity is attributable to phytochemicals in the extracts, including: phenols, terpenoids, flavonoids and anthraquinones. These findings could partly explain observed "positive" treatment outcome by indigenous people using these plant formulations.

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Section: Antitubercular and Antimicrobial Activity Screeningmentioning

confidence: 99%

Potency of extracts of selected plant species from Mbeere, Embu County-Kenya against Mycobacterium tuberculosis

Njeru¹,

Obonyo²

2016

J. Med. Plants Res.

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“…In another study, it was argued that W. somnifera shows its bactericidal and fungicidal activity through mechanisms attributed to cytotoxicity, gene silencing and immune potentiation, where aerial extract at concentration 1.56 mg/ml shows good antimicrobial potency (Mwitari et al, 2013). It is also shown to be a moderate to active against Microsporum gypseum, Candida albicans and Cryptococcus neoformans (Mwitari et al, 2013). Withanolide D, E and F showed potent activity against PknG target in Mycobacterium tuberculosis (Santhi and Aishwarya, 2011).…”

Section: Antimicrobial Activitymentioning

confidence: 99%

“…W. somnifera reported to exhibit antibacterial activities and it shows its activity against both Gram-positive and Gram-negative pathogenic bacteria (Singariya et al, 2012). In another study, it was argued that W. somnifera shows its bactericidal and fungicidal activity through mechanisms attributed to cytotoxicity, gene silencing and immune potentiation, where aerial extract at concentration 1.56 mg/ml shows good antimicrobial potency (Mwitari et al, 2013). It is also shown to be a moderate to active against Microsporum gypseum, Candida albicans and Cryptococcus neoformans (Mwitari et al, 2013).…”

Section: Antimicrobial Activitymentioning

confidence: 99%

Chemistry and pharmacology of withania somnifera: An update

Kumar¹,

Dey²,

Hadimani³

et al. 2015

TANG [HUMANITAS MEDICINE]

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Withania somnifera (Ashwagandha) is an important Rasayana herb and widely considered as Indian ginseng in Ayurveda. In traditional system of Indian medicine, it is used as tonic to rejuvenate the body and increase longevity. In Ayurvedic preparations, various parts of the plant have been used to treat variety of ailments that affect the human health. However, dried roots of the plant are widely used for the treatment of nervous and sexual disorders. The major active chemical constituents of this plant are withanolides, which is responsible for its wide range of biological activities. Since the beginning of the 20 th century, a significant amount of research has been done and efforts are ongoing to further explore other bioactive constituents, and many pharmacological studies have been carried out to describe their disease preventing mechanisms. In this chapter, we have reviewed the chemistry and pharmacological basis of W. somnifera in various human ailments.

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“…The method of Mwitari et al 13 was used with minor modifications. Briefly, 350g of dry powder material of different parts of DI were accurately weighed on an analytical balance, poured into separate conical flasks and soaked in 1 liter of distilled water and methanol separately for 48 h with frequent shaking.…”

Section: Extraction Of Different Plant Partsmentioning

confidence: 99%

Antiviral Activity of Dicrocephala Integrifolia (Kuntze) Against Herpes Simplex Type-1 Virus: An in vitro Study

Hadun¹,

Mbaria²,

Aboge³

et al. 2018

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Introduction: At present, acyclovir is commercially available as the drug of choice for managing herpes simplex type I (HSV-1) viral infection. However, the high prevalence of the infection coupled with the emergence of resistant viral strains has limited its effectiveness. Thus, the development of novel antiviral agents is crucial. Practitioners of herbal medicine in Kenya make use of Dicrocephala integrifolia (DI) for the management of several diseases including viral infections. However, information on the efficacy of this plant against HSV-1 viral infection is not available. The aim of the present study was to determine the in vitro antiviral activity of crude extracts of DI against HSV-1. Methods: Leaves, roots, flowers and stems of DI were extracted using water (W) and methanol (ME) and qualitatively screened to identify the phytoconstituents present. Furthermore, the anti HSV-1 activity of the obtained extracts was evaluated on Vero cell lines using the 3-[4, 5 dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide] assay. The 50% cytotoxic concentration (CC 50 ) and 50% effective concentration (EC 50 ) of each extract was determined using regression analysis. The effects of crude DI extracts on adsorption and post-adsorption stages of the HSV-1 replication cycle was evaluated against acyclovir using a cytopathogenic inhibition assay. Results: Alkaloids, glycosides, flavonoids, phenols, saponins, tannins and terpenoids were found to be present in the extracts. The CC 50 values of the aqueous DI extracts was in the range 71.31 ± 2.65 to >100 µg/ml compared to >100 µg/ml of acyclovir. The EC 50 values of crude extracts of DI on the pre-adsorptive phase of HSV-1 activity was in the range 54.45±3.45 to >100µg/ml compared to 4.772±7.81µg/ml of acyclovir whilst the EC 50 value of the crude extracts of DI on the post-adsorptive phase of HSV-1 activity was in the range 45.270±4.31 to >100µg/ml compared to >100µg/ml of acyclovir. Conclusion: The results suggest that crude extracts of DI may be a reservoir of phytochemicals with potentially good efficacy against HSV-1.

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Antimicrobial Activity and Probable Mechanisms of Action of Medicinal Plants of Kenya: Withania somnifera, Warbugia ugandensis, Prunus africana and Plectrunthus barbatus

Cited by 96 publications

References 19 publications

Potency of extracts of selected plant species from Mbeere, Embu County-Kenya against Mycobacterium tuberculosis

Potency of extracts of selected plant species from Mbeere, Embu County-Kenya against Mycobacterium tuberculosis

Chemistry and pharmacology of withania somnifera: An update

Antiviral Activity of Dicrocephala Integrifolia (Kuntze) Against Herpes Simplex Type-1 Virus: An in vitro Study

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