You can have in your Diet, but for greying hair would not suggest, better to use Thrive co hair prime serum. It has arcolys which helps to reverse the natural color. Takes little bit time but gives 100% resume.

As per me it's does not have a direct effect on preventing greying of hair

Hello hema, if you take them in youe meals it may help, but no research has proven the use of these leaves to prevent greving of hair