The four are Momilactone A, B, E (MA, MB, ME) and 7-ketostigmasterol (7KS), according to a study published in the Plants journal on June 7 by scientists from Nguyen Tat Thanh University in Ho Chi Minh City and Hiroshima University in Hiroshima, Japan.

MA and MB are capable of weed suppression in addition to inhibition of diabetes, obesity and gout, which the team had previously published. ME and 7KS also exhibited inhibitory capabilities though not as strong as that of MA and MB.

Tran Dang Xuan, head of the Plant Physiology and Biochemistry Laboratory at Hiroshima University and a member of the research team, said the four substances in rice husk were isolated and extracted through column chromatography, and later the structures of the compounds were determined using spectral techniques.

After determining the ratio of the four compounds in husk, the team continued to test their inhibitory abilities on cockspur grass and late goldenrod, two of many harmful and invasive plants that seriously affect rice production and harm the environment.

The team will focus on using MA, MB, ME and 7KS to inhibit weeds and invasive plants and develop safer, environment-friendly new herbicides.