Fungal resistance of obeche (Triplochiton Scleroxylon K. Schum) wood treated with neem (Azadirachta indica, A. Juss) seed oil extract

Abstract

This study aimed to providing eco-friendly wood preservatives from neem (Azadirachta indica) seed oil extract against wood decay fungi. Seed oil was extracted from the neem seed using soxhlet apparatus with N-hexane as the solvent. After extraction, the phytochemical screening of the oil was carried out. Sixty wood blocks of Triplochiton scleroxylon were treated with five different concentration levels (0 mL, 25 mL, 50 mL, 75 mL and 100 mL) of the seed oil extract and the untreated wood samples served as the control. The wood blocks were exposed to Sclerotium rolfsii (brown rot fungus) and Pleurotus ostreatus (white rot fungus) for 16 weeks and their weight loss determined. The phytochemical screening of the oil revealed that alkaloids (2141.7 mg/100g), tannins (975.0 mg/100g), flavonoids (1418.3 mg/100g), terpenoids (826.7 mg/100g), saponins (43.3mg/100g) and steroids (218.3mg/100g) were present. There were significant differences in the weight loss at different concentration levels at p< 0.05. The control has the highest weight loss of 36.48% ±2.03 and 47.89% ±2.34 for Pleurotus ostreatus and Sclerotium rolfsii respectively while the lowest weight loss for white and brown rot was 8.23% ± 1.07 and 11.84% ± 1.24 for Pleurotus ostreatus and Sclerotium rolfsii respectively. From this study, it is established that Azadirachta indica seed oil extract is a potential bio-preservative against wood decay fungi.

Keywords: Azadirachta indica, fungi, bio-deterioration, phytochemical screening