Question

what are natural indicator? what changes to acidic and to bases

Answer 1

The indicators which can be obtained from Plants directly and are natural .. those indicators are known as Natural Indicator.

Litmus is a Natural indicator 
It turns Blue in acidic Solution while it turns Red in Basic Solution.

Answer 2

natural indiactors are the pH indicators which are extracted from plants or plant compounds like purple cabbage, litmus, beetroot, tumeric, china rose.
Tumeric does not change it colour in acidic medium but changes colour in basic medium from yellow to red.
Purple cabbage turns purple to red in an acid and from purple to green in a base.
China rose changes its colour into magenta in acidic solutions and into green in basic solutions.