Pouteria campechiana leaf extract and its bioactive compound myricitrin are mosquitocidal against Aedes aegypti and Culex quinquefasciatus

Objective: To test the mosquitocidal potential of leaf extracts of Pouteria campechiana prepared with different solvents and elucidate the structure of an isolated mosquitocidal compound. Methods: The leaf extracts of Pouteria campechiana prepared with three solvents(petroleum benzene, ethyl acetate and acetone) and potential bioactive fractions were tested against various stages of Aedes aegypti and Culex quinquefasciatus by using the WHO protocols, and the chemical profile and its functional groups were identified by GC-MS and Fourier transmissioninfrared spectroscopy(FT-IR). The structure of bioactive compound was characterized by nuclear magnetic resonance(NMR) spectral technique. Results: The preliminary phytochemical results revealed the presence of alkaloids, amino acids, flavonoids, quinones, saponins, steroids, tannins, and terpenoids in the acetone extract. A significant toxic potential was observed in the acetone extract against both Aedes aegypti and Culex quinquefasciatus mosquitoes. The acetone extract exhibits remarkable larvicidal(LC50: 12.232 μg/mL and LC90: 63.970 μg/mL), pupicidal(LC50: 18.949 μg/mL and LC90: 167.669 μg/m L) and adulticidal(LC50: 20.689 μg/mL and LC90: 72.881 μg/mL) effects against Aedes aegypti. Furthermore, the same extract was subjected to isolation of bioactive compound by GCMS and FT-IR analysis. GC-MS results showed the presence of 5 major compounds, and octacosane(18.440%) was detected as the predominant compound. The FT-IR result of acetone extract demonstrated the presence of various functional groups like alkanes/alkynes, ester, aromatic and amides. The NMR spectrum results of isolated compound were well matched to glycoside linked flavonoids. Based on the chromatography and spectral techniques the isolate molecule was identified as myricitrin by FT-IR and nuclear magnetic resonance spectral data. Conclusion: The isolated compound myricitrin possesses a significant toxic effect in all stages of Aedes aegypti and Culex quinquefasciatus mosquito’s with lowest LC50 and LC90 values.

三种因素对蛋黄果嫁接繁育的影响

为满足蛋黄果生产需要,提高蛋黄果嫁接苗成活率,探索蛋黄果嫁接的适宜方式,以“仙桃1号”蛋黄果Pouteria campechiana‘Xiantao 1’为试材,以1.5年生,主干直径≥1.0 cm的实生苗为砧木,设置顶芽、半木质化枝条、木质化枝条不同接穗,劈接、切接和合接不同嫁接方法,春季、夏季、冬季不同时期嫁接,分别测定比较不同接穗、方法、时期嫁接处理的嫁接苗成活率。结果表明,接穗类型、嫁接方法及嫁接时期对“仙桃1号”蛋黄果嫁接成活率都具有显著的影响。其中,木质化枝条接穗的嫁接成活率最高,为99.33%,其次为半木质化枝条,嫁接成活率为80.00%,顶芽的嫁接成活率最低,仅为58.67%;劈接的嫁接成活率最高,为98.00%,切接次之,为80.00%,合接最低,为61.33%;春季嫁接的成活率最高,达到100%,且嫁接苗生长较旺盛;秋季嫁接的成活率次之,为85.33%,冬季嫁接的成活率最低,仅为55.33%,且植株长势较弱。因此,春季(3—4月)选取木质化枝条劈接是“仙桃1号”蛋黄果嫁接较适宜方法。

蛋黄果多酚的提取工艺及其抗氧化活性

研究蛋黄果的果肉多酚和种子多酚的提取以及其抗氧化活性将为蛋黄果的综合开发利用提供理论基础。在分析超声波辅助法提取果肉多酚和种子多酚单因素影响的基础上,运用响应面法优化多酚的提取工艺从而获得果肉多酚的最佳提取条件为乙醇浓度50%、提取时间102 min、提取温度62℃、料液比1∶30(g/mL);种子多酚的最佳提取条件为乙醇浓度40%、提取时间101 min、提取温度60℃、料液比1∶30(g/mL),此时果肉多酚和种子多酚提取率分别为0.74%、2.65%,与预测值(0.71%、2.69%)相接近。对1,1-二苯基-2-三硝基苯肼自由基(DPPH·)、羟自由基(·OH)、超氧阴离子自由基(O_(2)-·)的清除能力试验表明果肉多酚和种子多酚都具有较强抗氧化性,并与浓度呈正相关,且种子多酚的抗氧化活性高于果肉多酚,说明蛋黄果种子可以作为天然抗氧化剂的来源。

蛋黄果种子营养成分分析与评价

为了进一步开发和利用蛋黄果种子的潜在价值,对其主要营养成分、挥发油成分进行分析和检测,并研究了挥发油对5种细菌的抑制作用。结果表明:种子中淀粉、多糖、粗脂肪、多酚、灰分等成分含量较多,分别为13.89、8.04、6.27、2.58、2.22 g/100 g;Vc、黄酮、粗蛋白、氨基酸的含量分别为0.002、1.90、1.12、2.295 g/100 g。从种子挥发油中鉴定出22种化合物,主要成分为油酸、棕榈酸、邻苯二甲酸单(2-乙基己基)酯、芥酸酰胺,其相对百分含量分别为10.466%、8.158%、6.643%、4.216%。研究还证实蛋黄果种子挥发油对四联球菌、蜡状芽孢杆菌、白色葡萄球菌、大肠杆菌有抑制作用,其中对四联球菌和蜡状芽孢杆菌的抑制作用较强。鉴于蛋黄果种子的营养和药用价值丰富,建议大力开发和利用。

蛋黄果新品种‘蛋苹一号’性状的初步评价

对选育出来的蛋黄果新品种‘蛋苹一号’进行了植物学性状、农艺性状以及品质性状等并进行研究,结果表明:蛋黄果新品种‘蛋苹一号’具有结果早、丰产、稳产特性;果形端正,为苹果型,果形指数为0.8,平均单果重322 g,可食率高,总糖含量22.91%,甜度适中,维生素C含量高达70.40%,粗脂肪6.95%,总淀粉含量1.60%,可食率71.00%。此结果对该品种的生产应用及示范推广具有重要意义。