Insecticide Stemona alkaloids

The genus Stemona is the source of insecticidal principles alkaloids have been reported from Stemona and Croomia. Three species of Stemona S. australiana, S. sessilifolia, and S. luberosa) gave positive tests the last two were known earlier. 

An interesting approach toward the total synthesis of the Stemona alkaloid, (-)-stenine (25), which have been used in Chinese and Japanese folk medicine as insecticides, as drugs for the treatment of respiratory diseases, via spirolactone... 

There are six species of stemona plants growing in China Stemona tuberosa Lour. St. sessilifolia (Miq) French, et Savat, St. japonica (Blume) Miq., St. parviflora C.H. Wright, St. mairei Levi and Croomia japonica Miq. The first three plants are used in TCM and the latter three are used in folk medicine as insecticide, too. In the past, eleven stemona alkaloids have been separated from the roots of the first three Stemona plants and their structures were determined mostly by X-ray crystallography analyses due to the complexity of these structures. (Table 7 and Scheme 15) [58,59]. There are also several other stemona alkaloids, which have been reported, but their structures are unknown. 

Kongkiatpaiboon S, Gritsanapan W. Optimized extractitm for high yield of insecticidal didehydrostemofoline alkaloid in Stemona collinsiae root extracts. Ind Crop Prod 2013 41 371. ... 

In the course of a search for a-glucosidase inhibitors, Kitaoka et al. found that such inhibitors are present in some Thai traditional crude dmgs [39]. For example, a-HNJ occurs in Non tai yak at a level of 0.1 % (dry weight). The Non tai yak sample is known to be Stemona tuberosa (Stemonaceae), which has been used in China and Japan for various medicinal purposes. In particndar, an extract from the fresh tuberous roots of S. tuberosa is used to treat respiratory disorders, including pulmonary tuberculosis and bronciiitis, and is also recommended as an insecticide [27,40,41]. In 2005, re-examination of polyhydroxylated alkaloids in S. tuberosa led to the isolation of thirteen alkaloids, 1, 24,25,31,36,37 (0.1 % of dry weight), 38,40,41,... 

Stemofoline is an insecticidal alkaloid produced in the leaves and stems of the plant Stemona japonica. It has a good spectrum of activity, with rapid action, and is a potent agonist of the nicotinic acetylcholine receptor in insects. These features make it a promising lead, except that its highly complex polycyclic structure is a real challenge for synthesis (Figure 3). 

Sakata, K., K. Aoki, C. Chang, A. Sakurai, S. Tamura, and S. Murakoshi, Stemospironine, a new insecticidal alkaloid of Stemona japonica Miq. Isolation, structural determination and activity, Agric. Biol. Chem., 42, 457-463 (1978). 

The remarkable insecticide, vermifuge, and anticough activities reported for the Stemona extracts in the traditional medicine system of China and Japan (6,7,24,33,83 have motivated the study of the biological activity of the crude extracts of some Stemona species, as well as of the isolated alkaloids. 

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