Parkia timoriana (DC.) Merr. of the family Leguminosae (Fabaceae) and sub-family Mimosoideae, commonly known as tree bean is widely distributed throughout northeast India. It is considered to be a multipurpose tree, with various food and medicinal uses. The seeds are consumed at all developmental stages, and are considered to be a special delicacy due to their distinctive aroma and flavour. The characteristic sulphur aroma of the seeds is associated with the thiol amino acid derivative thioproline, which is a condensation product of formaldehyde and cysteine. In the present study, the presence of formaldehyde and thiol in the different developmental stages of the fruits were evaluated. The level of formaldehyde and thiol content was found to increase with the maturity of the seeds. The generation of sulfhydryl free radicals by thioproline and crude P. timoriana seed extracts on gamma irradiation were observed with the visible destruction of curcumin. The protection of DNA against gamma irradiation in the presence of thioproline in the present study also provides a new lead for investigations into protection against radiotherapy and reduction of risk for exposed individuals.