Phytochemical Investigation, Antioxidant and Antimycobacterial Activities of Schkuhria pinnata (Lam) Thell Extracts Against Mycobacterium smegmatis

Phytochemical composition and in vitro antioxidant and antimicrobial activities of Bersama abyssinica F. seed extracts

Medicinal plants can be potential sources of therapeutic agents. Traditional healers use a medicinal plant from Ethiopia, Bersama abyssinica Fresen, to treat various diseases. This study aimed to investigate the phytochemical components and antioxidant and antimicrobial activities of B. abyssinica seed extracts (BASE). Gas chromatography coupled to mass spectroscopy (GC-MS) analysis was used to determine the phytochemical compositions of BASE. The antioxidant activities were assessed by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, thiobarbituric acid-reactive species (TBARS) assay, ferric chloride reducing assay and hydroxyl scavenging capacity assay. Antimicrobial activity was investigated using the agar well diffusion method. Phytochemical screening showed the presence of saponins, glycosides, tannins, steroids, phenols, flavonoids, terpenoids, and alkaloids. GC-MS analysis revealed the presence of 30 volatile compounds; α-pinene (23.85%), eucalyptol (20.74%), β-pinene (5.75%), D-limonene (4.05%), and o-cymene (5.02%). DPPH-induced free radical scavenging (IC50 = 8.78), TBARS (IC50 = 0.55 µg/mL), and hydroxyl radicals' scavenging capacities assays (IC50 = 329.23) demonstrated high antioxidant effects of BASE. Reducing power was determined based on Fe3+-Fe2+ transformation in the presence of extract. BASE was found to show promising antibacterial activity against S. aureus, E. coli, and P. aeruginosa (zone of inhibition 15.7 ± 2.5 mm, 16.0 ± 0.0 mm, and 16.7 ± 1.5 mm, respectively), but excellent antifungal activities against C. albican and M. furfur (zone of inhibition 22.0 ± 2.0 mm and 22.0 ± 4.0 mm, respectively). The seeds of B. abyssinica grown in Ethiopia possess high antioxidant potential, promising antibacterial and superior antifungal activity. Therefore, seeds of B. abyssinica provide a potential source for drug discovery.

Developmental stages influence in vivo antimalarial activity of aerial part extracts of Schkuhria pinnata

ETHNOPHARMACOLOGICAL RELEVANCE

Malaria remains a dire health challenge, particularly in sub-Saharan Africa. In Uganda, it is the most ordinary condition in hospital admission and outpatient care. The country's meager health services compel malaria patients to use herbal remedies such as Schkuhria pinnata (Lam.) Kuntze ex Thell (Asteraceae). Although in vivo studies tested the antimalarial activity of S. pinnata extracts, plant developmental stages and their effect at different doses remain unknown.

AIM OF THE STUDY

This study aims to determine the effect of the plant developmental stage on the antimalarial activity of S. pinnata in mice and to document the acute oral toxicity profile.

METHODS

Seeds of S. pinnata were grown, and aerial parts of each developmental stage were harvested. Extraction was done by maceration in 70% methanol. The antimalarial activity was evaluated using chloroquine-sensitive Plasmodium berghei on swiss albino mice, in a chemosuppressive test, at 150, 350, and 700 mg/kg, p.o. Standard drugs used were artemether-lumefantrine (0.57 + 3.43) mg/kg and chloroquine (10 mg/kg) as positive controls. Distilled water at 1 mL/100g was used as a negative control. The Lorke method was adopted to determine the acute toxicity of extracts.

RESULTS

The flowering stage extract had a maximum suppression of parasitemia at 700 mg/kg (68.83 ± 4.49%). Extract at other developmental stages also significantly suppressed the parasitemia (in the ascending order) fruiting (50.71 ± 1.87%), budding (54.92 ± 7.56%), vegetative (55.39 ± 2.01%) compared to the negative control (24.7 ± 2.7%), p < 0.05. Extracts from all developmental stages increased survival time, with the flowering stage having the highest survival time at 20.33 ± 0.88 days. All extracts had an LD₅₀ of 2157 mg/kg, implying that extracts are safe at lower doses.

CONCLUSION

Together, our findings revealed that the S. pinnata extracts at the flowering stage had superior antimalarial activity compared to other plant developmental stages. Extracts from all developmental stages have demonstrated a dose-dependent suppression of malarial parasites and increased survival time with an LD₅₀ of 2157 mg/kg. Thus, for better antimalarial activity, local communities could consider harvesting S. pinnata at the flowering stage. Further studies are needed to isolate pure compounds from S. pinnata and determine their antimalarial activity.

The anti-nociceptive effects of ethanol extract of aerial parts of Schkuhria pinnata in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The growing challenge to access conventional analgesics, contraindications, and adverse effects could have led individuals to use Schkuhria pinnata (Lam.) Kuntze ex Thell. (Compositae), as an alternative traditional therapeutic strategy for pain. However, evidence of its safety and efficacy is scarce.

AIM OF THE STUDY

This study evaluated the anti-nociceptive effect of the ethanol extract of the aerial parts of S. pinnata in mice.

METHODS

The mice were randomly assigned to nine groups: (1) vehicle; (2) acetylsalicylic acid (intraperitoneally 150 mg/kg); (3) pentazocine (intramuscularly 1.0 mg/kg); (4 a & b) orally 100 mg/kg extract; (5 a & b) orally 200 mg/kg extract; (6 a & b) orally 400 mg/kg extract. We used an acetic acid-induced writhing model and a tail-flick test. The number of writhes and time taken for the tail to flick was recorded. A one-way analysis of variance followed by Tamhane T2 post hoc was used for multiple comparisons.

RESULTS

Compared to a vehicle (59.0 ± 2.68), S. pinnata ethanol extract at a dose of 200 and 400 mg/kg, p.o reduced writhes to 42.5 ± 1.12 and 27.0 ± 2.62, (p < 0.05) respectively. Similarly, the pain threshold of mice increased dose-dependently; doses of 200 and 400 mg/kg, increased time to 5.33 ± 0.42 and 8.67 ± 0.21 min, (p < 0.05) respectively. The extract had an EC50 of 348.8 mg/kg and acute toxicity established an LD50 of 1224.8 (95% CI: 952.2-1575.3).

CONCLUSION

S. pinnata ethanol extract had anti-nociceptive activity by central and peripheral mechanisms that could justify its traditional use in pain management. Further studies could now focus on identifying active fractions and pure isolated compounds responsible for anti-nociceptive activity.

The traditional use of southern African medicinal plants for the treatment of bacterial respiratory diseases: A review of the ethnobotany and scientific evaluations

ETHNOPHARMACOLOGICAL RELEVANCE

Multiple plant species were used traditionally in southern Africa to treat bacterial respiratory diseases. This review summarises this usage and highlights plant species that are yet to be verified for these activities.

AIM OF THE STUDY

This manuscript reviews the traditional usage of southern African plant species to treat bacterial respiratory diseases with the aim of highlighting gaps in the literature and focusing future studies.

MATERIALS AND METHODS

An extensive review of ethnobotanical books, reviews and primary scientific studies was undertaken to identify southern African plants which are used in traditional southern African medicine to treat bacterial respiratory diseases. We also searched for southern African plants whose inhibitory activity against bacterial respiratory pathogens has been conmfirmed, to highlight gaps in the literature and focus future studies.

RESULTS

One hundred and eighty-seven southern African plant species are recorded as traditional therapies for bacterial respiratory infections. Scientific evaluations of 178 plant species were recorded, although only 42 of these were selected for screening on the basis of their ethnobotanical uses. Therefore, the potential of 146 species used teraditionally to treat bacterial respiratory diseases are yet to be verified.

CONCLUSIONS

The inhibitory properties of southern African medicinal plants against bacterial respiratory pathogens is relatively poorly explored and the antibacterial activity of most plant species remains to be verified.

Evaluation of bioactive compounds, free radical scavenging and anticancer activities of bulb extracts of Boophone disticha from Eastern Cape Province, South Africa

Boophone disticha (B. disticha) is a bulbous tropical and subtropical flowering plant widespread in Africa, which is frequently used to treat several human ailments. Until the present, there is no scientific validation on the biological activity of this plant from the Eastern Cape Province of South Africa and as a result, this study aimed to assess the bioactive compounds, free radicals scavenging and anticancer potentials of crude bulb extracts (chloroform, acetone, and ethanol) of Boophone disticha obtained from this geographical location. Standard biochemical techniques and Gas-chromatography mass spectrometry (GCMS) analysis were used to pinpoint the bioactive compounds in the crude extracts sequel to their antioxidant potentials against radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide and nitric oxide as well as their ferric ion reducing power. In addition, their cytotoxicity effects against Human cervix adenocarcinoma (HeLa) cells were assessed as an in vitro model for anticancer. The phytochemical evaluation of the crude extracts showed the presence of phenolics, flavonoids, and alkaloids. GCMS profiles confirmed the presence of some bioactive compounds in the crude extracts of B. disticha that could be responsible for their biological activities. The plant extracts possessed considerable antioxidant activity and exhibited dose-dependent radicals’ inhibition from all assays carried out. Furthermore, the cytotoxicity effects against HeLa cells recorded inhibition concentration (IC₅₀) of 1.5, 1.6, and 1.9 µg/mL for acetone, chloroform, and ethanolic extracts of B. disticha, respectively. Findings from the present study suggest that B. disticha could be a good prospective source of antioxidant and anticancer agents. Therefore, further research on the isolation and purification of compounds from these extracts are indispensable.

Efficacy and Mechanisms of Flavonoids against the Emerging Opportunistic Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are the causative agent of severe chronic pulmonary diseases and is accountable for post-traumatic wound infections, lymphadenitis, endometritis, cutaneous, eye infections and disseminated diseases. These infections are extremely challenging to treat due to multidrug resistance, which encompasses the classical and existing antituberculosis agents. Hence, current studies are aimed to appraise the antimycobacterial activity of flavonoids against NTM, their capacity to synergize with pharmacological agents and their ability to block virulence. Flavonoids have potential antimycobacterial effects at minor quantities by themselves or in synergistic combinations. A cocktail of flavonoids used with existing antimycobacterial agents is a strategy to lessen side effects. The present review focuses on recent studies on naturally occurring flavonoids and their antimycobacterial effects, underlying mechanisms and synergistic effects in a cocktail with traditional agents.

Testing the Antimicrobial Characteristics of Wood Materials: A Review of Methods

Some wood species have antimicrobial properties, making them a better choice over inert surfaces in certain circumstances. However, the organic and porous nature of wood raises questions regarding the use of this material in hygienically important places. Therefore, it is reasonable to investigate the microbial survival and the antimicrobial potential of wood via a variety of methods. Based on the available literature, this review classifies previously used methods into two broad categories: one category tests wood material by direct bacterial contact, and the other tests the action of molecules previously extracted from wood on bacteria and fungi. This article discusses the suitability of these methods to wood materials and exposes knowledge gaps that can be used to guide future research. This information is intended to help the researchers and field experts to select suitable methods for testing the hygienic safety and antimicrobial properties of wood materials.