印楝各部位水提取物和乙醇提取物对……真菌腐烂病的抑制作用

Ezeonu Chukwuma Stephen, Tatah Verwiyeh Silas, Imo Chinedu, Mamma Emmanuel, Mayel Mida Habila, Kukoyi Ayobami Jahdahunsi, Jeji Ibrahim Adams

Pak J Biol Sci. 2019 Jan;22(5):206-213. doi: 10.3923/pjbs.2019.206.213.

BACKGROUND AND OBJECTIVE

The processing and preservation of Irish potato tubers like many other crops has been affected by various pathogens like fungi (particularly storage rot) which causes a major constraint to Irish potato production in Nigeria resulting to enormous post-harvest spoilage. The inhibitory effect of aqueous and ethanolic extracts of neem leaves, stem bark and seeds on fungal rot disease of Solanum tuberosum (Irish potato) as an alternative treatment for fungal storage disease on Irish potato tubers cultivated in Nigeria has been determined in this study.

MATERIALS AND METHODS

Neem parts were harvested from Wukari, Nigeria and were processed for the experiment. Isolation of fungi and sub-culturing of the isolates was carried out to obtain pure culture. Pathogenicity study was carried out and effect of the plant extracts on mycelia growth of the test fungi was studied using the food poisoning techniques. The qualitative and quantitative phytochemical studies of the neem parts were carried out using standard methods.

RESULTS

Qualitative phytochemical screening of the selected parts of neem plant showed the presence of alkaloids, glycoside, flavonoids, carbohydrates, reducing sugar, steroids, tannins and saponins. The quantitative test revealed that the percentage quantity of phytochemicals in these plant parts ranged from 10.17-23.88%. Effect of the extracts on the test organisms was significant (p<0.05). Ethanolic extract of the seed (ESE) exhibited the highest inhibitory effect on Aspergillus niger (88.37%) followed by aqueous extract of stem bark (ABE) (87.21%), while aqueous seed extract (ASE), ethanolic leaves extract (ELE), aqueous leaves extract (ALE) and ethanolic stem bark extract (EBE) exhibited inhibition of 81.78, 77.52, 72.87 and 39.53%, respectively. The inhibitory effect of EBE was significantly (p<0.05) lower than that of other extracts, while there was no significant difference in the inhibitory effects of ESE, ASE and ABE compared to ketoconazole on Aspergillus niger. The ethanolic extracts of the seed and leaves had 100% inhibitory effect on Fusarium oxyporium with 87.60% inhibition by aqueous extract of the leaves. The seed and the leaves ethanolic extracts exhibited the highest inhibitory effects on Pythium spp. and Fusarium oxyporium, while the aqueous leaves extract showed the least inhibition on Fusarium oxyporium.

CONCLUSION

The plant extracts in this study were found to be very effective in inhibiting fungal mycelia growth and hence can be potentially effective for preservation during storage of Irish potatoes to minimize post-harvest lost.

背景与目的

与许多其他作物一样，爱尔兰马铃薯块茎的加工和保存受到各种病原体的影响，如真菌（尤其是贮藏腐烂），这对尼日利亚的爱尔兰马铃薯生产造成了重大限制，导致大量收获后损失。本研究确定了印楝叶、茎皮和种子的水提取物和乙醇提取物对马铃薯（爱尔兰马铃薯）真菌腐烂病的抑制作用，作为尼日利亚种植的爱尔兰马铃薯块茎真菌贮藏病害的替代处理方法。

材料与方法

从尼日利亚的武卡里采集印楝各部位并进行加工用于实验。进行真菌分离和分离物的继代培养以获得纯培养物。进行致病性研究，并使用食物中毒技术研究植物提取物对试验真菌菌丝体生长的影响。采用标准方法对印楝各部位进行定性和定量植物化学研究。

结果

对印楝植物选定部位的定性植物化学筛选显示存在生物碱、糖苷、黄酮类、碳水化合物、还原糖、甾体、单宁和皂苷。定量试验表明，这些植物部位中植物化学物质的百分比含量在10.17 - 23.88%之间。提取物对试验生物的影响显著（p<0.05）。种子乙醇提取物（ESE）对黑曲霉的抑制作用最高（88.37%），其次是茎皮水提取物（ABE）（87.21%），而种子水提取物（ASE）、叶乙醇提取物（ELE）、叶水提取物（ALE）和茎皮乙醇提取物（EBE）的抑制率分别为81.78%、77.52%、72.87%和39.53%。EBE的抑制作用显著低于其他提取物（p<0.05），而与酮康唑相比，ESE、ASE和ABE对黑曲霉的抑制作用无显著差异。种子和叶的乙醇提取物对尖孢镰刀菌有100%的抑制作用，叶水提取物对尖孢镰刀菌的抑制率为87.60%。种子和叶的乙醇提取物对腐霉菌和尖孢镰刀菌的抑制作用最高，而叶水提取物对尖孢镰刀菌的抑制作用最小。