Primera descripción de Sclerotium coffeicola en caoba africana en México / First description of Sclerotium coffeicola on African mahogany in Mexico

Una enfermedad foliar fue detectada en la plantación comercial de Khaya senegalensis con 3 anos de edad, en la localidad de Huimanguillo (Tabasco, México). Mediante la caracterización morfológica y molecular, y por el cumplimiento de los postulados de Koch, se determinó que el agente causal corresponde al hongo Sclerotium coffeicola. Este es el primer reporte de S. coffeicola causando mancha foliar en caoba africana en México.

A foliar disease was detected in the commercial plantation of Khaya senegalen with three years of age in Huimanguillo, Tabasco, Mexico. Through the morphological and molecular characterization and the compliance of the Koch's postulates, it was concluded that the causal agent corresponds to the fungus Sclerotium coffeicola. This is the first report of S. coffeicola causing leaf spot on African mahogany in Mexico.

Studies on the antibacterial activity of Khaya senegalensis [(Desr.) A. Juss)] stem bark extract on Salmonella enterica subsp. enterica serovar Typhi [(ex Kauffmann and Edwards) Le Minor and Popoff]

Objective: To study the phytochemical screening and antibacterial activity of the stem bark extracts ofKhaya senegalensis (K. senegalensis) against Salmonella enterica subsp. enterica serovar Typhi. Methods: The plant components were extracted using methanol, ethanol and water. The phytochemical screening of the stem bark extracts were carried out using a standard method. The antibacterial assay of the stem bark extracts against Salmonella Typhi (S. Typhi) using the agar well diffusion method with different concentrations of 50, 100, 200, 400 and 500 mg/mL and the corresponding concentrations of the control was carried out and the result compared with a standard antibiotic, amoxicillin as the control.Results:The results obtained from the phytochemical screening of the three plant bark extracts of K. senegalensis showed 10 plant secondary metabolites including saponins, tannins, reducing sugars, aldehyde, phlobatannins, flavonoids, terpenoids, alkaloids, cardiac glycoside and anthroquinones. The ethanol and aqueous extracts showed antibacterial activities against S. Typhi at concentration of 50 mg/mL with the zone diameter of inhibition (ZDI) of 14 mm and 15 mm respectively. The ethanol and aqueous extracts also showed zone diameter of inhibition of 23 mm and 25 mm respectively at 250 mg/mL and 27 mm each at 500 mg/mL. The ethanol and aqueous stem bark extracts gave the highest ZDI at 500 mg/mL while 100 mg/mL gave the least ZDI for ethanol extract and 50 mg/mL for the aqueous extract. This was followed by 400 mg/mL that gave 24 mm ZDI of the aqueous extract and 27 mm of the ethanol extract. The methanol extract showed intermediate susceptibility evidenced by ZDI of 10 mm at 100 mg/mL concentration. The methanol extract also showed antibacterial activity of 24 mm ZDI against the test organism at a higher concentration of 250 mg/mL and 26 mm at 500 mg/mL concentration. The methanol, ethanol and aqueous extracts displayed antibacterial activities against S. Typhi with a statistical significant difference at (P≤0.05). The extracts compared favourably with the standard antibiotic, the control. The minimum inhibitory concentration of the extracts was 250, 200, 200 and 100 mg/mL for methanol, ethanol, aqueous extracts and amoxicillin (control) respectively. The minimum lethal concentration of the extracts was 250, 250, 400 and 200 mg/mL for methanol, ethanol, aqueous extracts and control respectively.Conclusions:The antibacterial properties of K. senegalensis stem bark extract can be harnessed for the production of new antibiotics or the enhancement of already existing antibiotics.

Studies on the antibacterial activity of Khaya senegalensis (Desr.) A. Juss) stem bark extract on Salmonella enterica subsp. enterica serovar Typhi (ex Kauffmann and Edwards) Le Minor and Popoff

<p><b>OBJECTIVE</b>To study the phytochemical screening and antibacterial activity of the stem bark extracts of Khaya senegalensis (K. senegalensis) against Salmonella enterica subsp. enterica serovar Typhi.</p><p><b>METHODS</b>The plant components were extracted using methanol, ethanol and water. The phytochemical screening of the stem bark extracts were carried out using a standard method. The antibacterial assay of the stem bark extracts against Salmonella Typhi (S. Typhi) using the agar well diffusion method with different concentrations of 50, 100, 200, 400 and 500 mg/mL and the corresponding concentrations of the control was carried out and the result compared with a standard antibiotic, amoxicillin as the control.</p><p><b>RESULTS</b>The results obtained from the phytochemical screening of the three plant bark extracts of K. senegalensis showed 10 plant secondary metabolites including saponins, tannins, reducing sugars, aldehyde, phlobatannins, flavonoids, terpenoids, alkaloids, cardiac glycoside and anthroquinones. The ethanol and aqueous extracts showed antibacterial activities against S. Typhi at concentration of 50 mg/mL with the zone diameter of inhibition (ZDI) of 14 mm and 15 mm respectively. The ethanol and aqueous extracts also showed zone diameter of inhibition of 23 mm and 25 mm respectively at 250 mg/mL and 27 mm each at 500 mg/mL. The ethanol and aqueous stem bark extracts gave the highest ZDI at 500 mg/mL while 100 mg/mL gave the least ZDI for ethanol extract and 50 mg/mL for the aqueous extract. This was followed by 400 mg/mL that gave 24 mm ZDI of the aqueous extract and 27 mm of the ethanol extract. The methanol extract showed intermediate susceptibility evidenced by ZDI of 10 mm at 100 mg/mL concentration. The methanol extract also showed antibacterial activity of 24 mm ZDI against the test organism at a higher concentration of 250 mg/mL and 26 mm at 500 mg/mL concentration. The methanol, ethanol and aqueous extracts displayed antibacterial activities against S. Typhi with a statistical significant difference at (P≤0.05). The extracts compared favourably with the standard antibiotic, the control. The minimum inhibitory concentration of the extracts was 250, 200, 200 and 100 mg/mL for methanol, ethanol, aqueous extracts and amoxicillin (control) respectively. The minimum lethal concentration of the extracts was 250, 250, 400 and 200 mg/mL for methanol, ethanol, aqueous extracts and control respectively.</p><p><b>CONCLUSIONS</b>The antibacterial properties of K. senegalensis stem bark extract can be harnessed for the production of new antibiotics or the enhancement of already existing antibiotics.</p>

Bioactivity, therapeutic utility and toxicological risks of Khaya senegalensis.

Vegetative organs of Khaya senegalensis (Ders.) A. Juss. are widely used in African pharmacopoeia. A review of pharmacological studies, focused on this plant, was carried out, using the available scientific literature. Several studies have revealed its bioactive properties and therefore its medical efficacy. Aqueous and alcoholic extracts of the stem bark and leaves of this plant have shown efficient in the treatment of some bacterial infections. Their widely reported biochemical effects, such as -amylase activity inhibition, decreasing in bowel motility and in some blood and serum enzyme (Aspartate transferase, Alanine transferase and Alkaline phosphatase) justify indications against diabetes, diarrhea and liver disorders. Antiparasitic properties directed against helminths and coccidian are also attributed to these herbal medicines. However, according to some results recorded in various studies, this plant has a high risk of toxicity in chronic treatment (several weeks). Histotoxic effects (in liver and kidney) resulting in increased of plasma total protein, blood urea and creatinine are reported.

Evaluation of Anti-inflammatory and Antinociceptive Potentials of Khaya senegalensis A. Juss (Meliaceae) Stem Bark Aqueous Extract.

Aim: To investigate anti-inflammatory and antinociceptive potentials of aqueous stem bark extract of Khaya senegalensis A. Juss (Meliaceae) in rodents. Methodology: Anti-inflammatory activity of aqueous stem bark extract of K. senegalensis (AKS) was studied in different models. Effect of the extract in acute inflammation was tested in carrageenan-induced rat paw edema and its effect in chronic inflammation was evaluated using cotton pellet-induced granuloma test. Croton oilinduced ear edema in mice was used to investigate the effect of the extract on topical inflammation. Antinociceptive property of AKS was evaluated using three models of nociception: hot-plate test, acetic acid-induced writhing in mice and formalin-induced paw licking in rats. Membrane stabilizing effect of AKS was tested in heat and hypotonicity-induced hemolysis. The mechanism of antinociceptive effect of the extract was evaluated by pre-treating rats with metoclopramide, a dopamine (D2) antagonist (1.5 mg/kg body wt.) and naloxone, an opioid receptor antagonist (5 mg/kg body wt.). One hour after these treatments, the rats were given AKS (150 mg/kg p.o) and their reaction time in hot-plate was assessed. Free-radical scavenging activity of the extract was measured by decrease in the absorbance of 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) methanol solution. Results: The extract produced significant (P<0.05) and dose-dependent inhibition of ear edema in mice. It also caused a significant (P<0.05) reduction in granuloma formation and paw edema in rats. At concentration range of 125 - 500 μg/ml, AKS significantly (P<0.05) protects the erythrocyte membrane against lysis induced by heat and hypotonic medium. It also significantly (P<0.05) reduced the licking/biting time of the formalininjected rat paw in the early (19 - 51 % reduction) and late (13 - 57 % reduction) phases. The extract demonstrated significant (P<0.05) antinociceptive activity in the hot-plate and writhing tests and exhibited good scavenging effect on DPPH free radical. Conclusion: The study demonstrated that Khaya senegalensis stem bark aqueous extract possesses anti-inflammatory activity and antinociceptive effect mediated via central and peripheral mechanisms. Further studies on the plant may produce lead molecules for the development of new anti-inflammatory drugs.