Petchidurai Ganeshan, Sahayaraj Kitherian, Al-Shuraym Laila A, Albogami Bader Z, Sayed Samy M
Crop Protection Research Centre (CPRC), Department of Zoology, St. Xavier's College (Autonomous), Palayamkottai, Tirnelveli 627002, Tamil Nadu, India.
Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
Plants (Basel). 2023 Sep 6;12(18):3188. doi: 10.3390/plants12183188.
Seaweeds, also known as marine macroalgae, are renewable biological resources that are found worldwide and possess a wide variety of secondary metabolites, including tannins. Drifted brown seaweed (DBSW) is particularly rich in tannins and is regarded as biological trash. The cotton leaf hopper (Distant) has caused both quantitative and qualitative losses in cotton production. Drifted brown seaweeds (DBSWs) were used in this study to extract, qualitatively profile, and quantify the levels of total tannins, condensed tannins, hydrolyzable tannins, and phlorotannins in the seaweeds; test their insecticidal activity; and determine the mechanism of action. The largest amount of tannin extract was found in Greville (20.62%) using the Soxhlet method (SM). Significantly higher amounts of hydrolyzable tannins ( = 0.005), soluble phlorotannins ( = 0.005), total tannins in the SM ( = 0.003), and total tannins in the cold percolation method ( = 0.005) were recorded in . However, high levels of condensed tannins (CTAs) were observed in (Turner) J. Agardh ( = 0.004). nymphs and adults were examined for oral toxicity (OT) and contact toxicity (CT) against DBSW tannin crude extract and column chromatographic fractions 1 (Rf = 0.86) and 2 (Rf = 0.88). (J.V. Lamouroux) J. Agardh crude tannin was highly effective against using the OT method (LC, 0.044%) when compared with the standard gallic acid (LC, 0.044%) and tannic acid (LC50, 0.122%). Similarly, fraction 2 (LC, 0.007%) showed a greater insecticidal effect against adults in OT than gallic acid (LC, 0.034%) and tannic acid (LC, 0.022%). The mechanism of action results show that adults treated with crude tannin of had significantly decreased amylase, protease ( = 0.005), and invertase ( = 0.003) levels when compared with the detoxification enzymes. The levels of glycosidase, lactate dehydrogenase, esterase, lipase, invertase, and acid phosphate activities ( = 0.005) of were reduced when compared with those of the Vijayneem and chemical pesticide Monocrotophos. In adult insects treated with LC concentrations of tannin fraction 1, the total body protein (9.00 µg/µL) was significantly reduced (OT, LC-0.019%). The SDS-PAGE analysis results also show that tannin fraction 1 (OT and CT), fraction 2 (OT), and fraction 2 (CT) had a significant effect on the total body portion level, appearance, and disappearance of some proteins and polypeptides. This study shows that the selected brown macroalgae can be utilized for the safer management of cotton leaf hoppers.
海藻，也被称为海洋大型藻类，是一种可再生生物资源，在全球范围内都有发现，并拥有多种次生代谢产物，包括单宁。漂流褐藻（DBSW）尤其富含单宁，被视为生物垃圾。棉叶蝉（Distant）已给棉花生产造成了数量和质量上的损失。本研究使用漂流褐藻来提取、定性分析和定量测定海藻中单宁、缩合单宁、水解单宁和间苯三酚单宁的含量；测试它们的杀虫活性；并确定其作用机制。使用索氏提取法（SM）在格氏藻中发现了最大量的单宁提取物（20.62%）。在该藻中记录到的水解单宁（P<0.005）、可溶性间苯三酚单宁（P<0.005）、索氏提取法中的总单宁（P<0.003）以及冷渗滤法中的总单宁（P<0.005）含量显著更高。然而，在绳藻（Turner）J. 阿加德中观察到高水平的缩合单宁（CTAs）（P<0.004）。对棉叶蝉若虫和成虫进行了针对DBSW单宁粗提物以及柱色谱馏分1（Rf = 0.86）和2（Rf = 0.88）的口服毒性（OT）和接触毒性（CT）测试。与标准没食子酸（LC50，0.044%）和单宁酸（LC50，0.122%）相比，绳藻（J.V. 拉穆鲁）J. 阿加德的粗单宁在口服毒性测试中对棉叶蝉非常有效（LC50，0.044%）。同样，馏分2（LC50，0.007%）在口服毒性测试中对棉叶蝉成虫显示出比对没食子酸（LC50，0.034%）和单宁酸（LC50，0.022%）更大的杀虫效果。作用机制结果表明，与解毒酶相比，用绳藻粗单宁处理的棉叶蝉成虫的淀粉酶、蛋白酶（P<0.005）和转化酶（P<0.003）水平显著降低。与印楝素和化学农药久效磷相比，棉叶蝉的糖苷酶、乳酸脱氢酶、酯酶、脂肪酶、转化酶和酸性磷酸酶活性（P<0.005）降低。在用LC50浓度的绳藻单宁馏分1处理的成年昆虫中，总体蛋白（9.00 µg/µL）显著降低（口服毒性，LC50 - 0.019%）。SDS - PAGE分析结果还表明，绳藻单宁馏分1（口服毒性和接触毒性）、馏分2（口服毒性）以及绳藻馏分2（接触毒性）对总体蛋白水平、一些蛋白质和多肽的出现和消失有显著影响。本研究表明，所选的褐藻可用于更安全地防治棉叶蝉。
