Evaluation of antibacterial, antioxidant, and anti-inflammatory properties of GC/MS characterized methanol leaf extract of Terminalia superba (Combretaceae, Engl. & Diels)

Background

Terminalia superba is a well-known medicinal plant used in folk medicine for the management of various diseases and swelling. Validation of its efficacy in standardized scientific models is lacking. This gap needs to be filled as a way of enhancing modern drug discovery. The aim is to evaluate the antibacterial, antioxidant, and anti-inflammatory properties of T. superba in known and established models. Also, to establish and possibly correlate the established activity with the phytochemicals identified using GC/MS and qualitative methods.

Results

The result showed a dose-dependent percentage inhibition of DPPH, HO•, and Fe3+ reducing activity. The antibacterial activity showed dose-dependent significant (p < 0.05) inhibition against all the organisms used. The anti-inflammatory activity of METS was confirmed in the carrageenan model with significant (p < 0.05) inhibition of paw volume when compared to control while significantly decreasing (p < 0.05) weight of xylene-induced ear. For instance, after 6 h, there was  a reduction of 42%, 33%, and 22% for diclofenac, 200 mg, and 100 mg, respectively, as against 4% in control. The significant (p < 0.05) increase in MDA was attenuated by the treatment with METS dose dependently. Phytochemical assay and GC/MS characterization showed that alkaloids, saponins, phenols, quinone, tannins, coumarins, proteins, flavonoids, and amino acids were dominant with fatty acids accounting for 53%. Others are esters (23%), organic compounds (12%), alkanes (9%), and carboxylic acids (3%).

Conclusions

T. superba possesses antioxidant, antibacterial, and anti-inflammatory properties which are believed to arise from the secondary metabolites observed in the GC–MS characterization.

Graphical Abstract

Dietary supplementation of Pleurotus tuber regium in rat feed ameliorates metabolic and hematotoxicity induced by carbon tetrachloride

Pleurotus tuber regium, a wild edible mushroom can reduce free radical-mediated injury and oxidative stress induced by carbon tetrachloride (CCl4) via improvement of antioxidant capacity. This work evaluates the protective effects of this mushroom against the metabolic and hematological toxicity induced by CCl4. Sixty male Sprague Dawley rats were divided into six groups (n = 10). Group I received olive oil (3 mL/kg) i.p. twice weekly for 13 weeks, while maintaining free access to food and water ad libitum (negative control). Group II received 3 mL/kg (30% CCl4 in olive oil) injected i.p. twice weekly, while Groups III, IV, and V received 100, 200, and 500 mg wild edible P. tuber regium (33.3% in feed) daily in addition to 3 mL/kg CCl4 in olive oil injected twice weekly i.p. Group VI received olive oil (3 mL/kg) i.p. twice weekly for 13 weeks in addition to 500 mg P. tuber regium (33.3% in feed) daily. The body weight (b.w.), feed intake (FI), and water intake (WI) were obtained weekly, while the hematological indices and oxidative stress parameters were carried out shortly after necropsy on days 30, 60, and 90. Treatment with CCl4 significantly (p < 0.05) decreased the b.w., FI and WI, feed efficiency, ascorbic acid, α-tocopherol, and antioxidant enzymes, superoxide dismutase, catalase, total glutathione, and peroxidase, while increasing the oxidative stress as measured by malondialdehyde in CCl4 only group when compared with control. Supplementation of feed with P. tuber regium reversed the effects of CCl4. Pleurotus tuber regium ameliorated the CCl4-induced metabolic and hematotoxicity by improving the antioxidant capacity.

Potential hazards of toxic metals found in toothpastes commonly used in Nigeria

BACKGROUND

Toothpastes have multi-functional configurations as oral care products. They can however constitute a pos- sible source, amongst others, of toxic metal exposure in public health. Indeed, the public health impact of personal hygiene and consumer products is largely unknown.

OBJECTIVE

To determine the level of toxic metals (lead, cadmium, cobalt, chromium, nickel) in toothpastes available in Nigeria, (home produced and imported), and assess the potential risk to the people.

MATERIAL AND METHOD

The samples of toothpastes commonly used in Nigeria were tested. Using a market basket protocol thirty five different brands of toothpaste were used. Samples were digest by addition of 10 mL mixture of conc. nitric and hydrochloric acids (HCl:HNO(3), 3:1), followed by heating to dryness. 20 mL deionized water was added, stirred and filtered. The filtrate was made up in standard volumetric flask and lead, cadmium, chromium, cobalt and nickel concentrations were determined using the atomic absorption spectrophotometry 205A. The daily intake of metals and target hazard quotient (THQ) were then calculated.

RESULTS

Pepsodent and Flodent had the highest levels of lead at respectively 23.575 and 18.092 mg/kg while Colgate Herbal had the highest nickel of 18.535 mg/kg. The daily intake estimates of all imported toothpaste samples were below the stated upper limits (UL). All target hazard quotients were also found to be below one.

CONCLUSIONS

Although the UL, THQ and daily intake rates were all normal, the high levels of lead in some of the tooth- pastes an important concern to public health suggesting that pre-marketing safety studies of toothpastes may be worthwhile for the regulatory authorities.

Human health hazards of poly aromatic hydrocarbons in Nigerian smokeless tobacco

Recently we investigated the heavy metal hazards of Nigerian smokeless tobacco products 'STP'. Since 'STPs' are advocated as safer alternatives to cigarets, the public health implication should be ascertained. This is a risk assessment of poly aromatic hydrocarbons 'PAHs' in 'STPs' used in Nigeria. Thirty 'STPs' from different parts (South East, South West, Niger Delta and North Central) of Nigeria were studied. The 15 PAHs were assayed using gas chromatographic system (6890 series and 6890 plus) equipped with a quadrupole Mass Spectrometer (Agilent 5975 MSD) after ultrasonic extraction of the 'STPs' and clean up of the extract. Toxicity equivalent of benzo[a]pyrene concentration(μg/kg) in 'STPs'were determined. The daily exposure and the cancer risk associated with exposure to STP were calculated. Sample A1 (south east) had the highest concentration of PAH 225.84 μg/kg, while sampleA3 (North central) had the least PAH concentration of 1.09 μg/kg. 'STPs' from South East showed highest levels of PAHs. The total B[a]P TEQ of the 'STPs' from the South East ranged from 0.24 to 29.23, South West ranged from 0.94 to 14.55, Niger Delta ranged from 2.28 to 22.88, and North Central ranged from 0.11 to 9.47. The calculated risk estimates for 'STPs' from the South East ranged from 5.43 E-05 to 4.50 E-07, South West 2.70 E-05 to 1.74 E-06, Niger Delta 4.30 E-05 to 4.20 E-06, and North Central 1.75 E-05 to 2.08 E0-7. Although the calculated risk estimates seem to be within or below the the U.S. EPA cancer risk range of 1 × 10-4-1 × 10-6, the total B[a]P TEQ of the STPs suggest a more indepth risk assessment in animal model to ascertain the safety of PAHs in Nigerian 'STPs'.