Flavonoid glycosides in Malabar spinach Basella alba inhibit the growth of Spodoptera litura larvae

Basella alba is a perennial plant of the Basellaceae and is known by various common names including Malabar spinach. There are few insects that cause damage to B. alba. In this study, we examined the effect of B. alba leaves on the growth of Spodoptera litura larvae. B. alba leaves and a methanolic extract of the leaves inhibited the growth of S. litura larvae. Half of the larvae reared on the leaves died within 1 week. We found that two flavonoids, vitexin, and vitexin-2″-O-arabinofuranoside, were abundant in the methanol extract of leaves. When larvae were reared on purified vitexin or vitexin-2″-O-arabinofuranoside, their growth was significantly impaired compared with larvae reared on control spinach leaves. These results suggested that the flavonoid glycosides in B. alba leaves act as deterrents to S. litura larvae.