Lannea coromandelica

Islam, M.T. and Tahara, S., Dihydroflavonols from Lannea coromandelica. Phytochemistry, 54, 901, 2000. 

Only 15 newly reported simple dihydroflavonols are listed in Table 15.9. Several of the compounds are just simply the C-3 epimers of known (2i ,3i )-dihydroflavonols, e.g., (2R,3S)-3-hydroxy-5,7-dimethoxyflavanone (329) from the fern Woodsia scopulina (Dryopterida-ceae), (2i ,3S)-3,5,3, 4 -tetrahydroxy-7-methoxyflavanone (3-epipadmatin, 333) from Inula graveolens (Asteraceae),(2i ,3S)-3,5,3 -trihydroxy-7,4 -dimethoxyflavanone (337) from Lannea coromandelica (Anacardiaceae), and (2i ,3S)-3,5,7,3, 4, 5 -hexahydroxyflavanone (hovenitin III, 338) from the seeds and fruits of Hovenia dulcis (Rhamnaceae). The previously known (2i ,3i )-stereoisomer of hovenitin III has the trivial name ampelopsin. The same plant source has yielded the (27 ,37 )- and (27 ,3S)-epimers of 3,5,7,4, 5 -pentahydroxy-3 -methoxyflavanone, which are known as hovenitins I (340) and II (341), respectively. ... 

Lannea coromandelica L. (Anacardiaceae) is a deciduous tree widely distributed in Bangladesh, India and some other tropical countries. Plants belonging to this genus are used in folk medicine for treatment of elephantiasis, impotence, ulcers, vaginal troubles, halitosis, heart disease, dysentery, gout and rheumatism [108]. Stem bark extracts of L. coromandelica exhibited potent zoospore motility inhibitory activity followed by characteristic lysis. Identification of active principles and their mode of action toward zoospores are briefly discussed here. 

Fig. (8). Possible structural units (A-D) of Lannea coromandelica (stem bark) polyflavonoid tannins, and structures of typical linear-and angular-type trimers.

Fig. (9), MALDI-TOF mass spectrum of Lannea coromandelica extract, Insels showing expanded form of some important parts of the MALD1-TOF-MS spectrum [113]. For each oligomer, substructures with mass increments of 16 Da appear, indicating different combinations of various substrutures.

The saponins such as avenacin Ai which is released from oat roots are known to be lytic to a broad range of oomycete zoospores. Our screening assays revealed that crude extract of stem bark bom an Anacardiaceae plant, Lannea coromandelica had similar properties. A solution of 200 ppm of the crude extract was found to inhibit the motility of the zoospores and subsequently cause them to lyse (3i). 

---