Gumemela is also popularly known as Hibiscus. It is one of the natural acid indicator. It contains anthocyanins that change color with varying pH levels. Where as litmus paper change of color to red/pink is an indicator that the substance is acidic. It is method to determine the ph level of a substance.
Now coming to your query - if hibiscus i.e. Gumamela is more sensitive to litmus, the answer is no because litmus test provides more accurate ph level then hibiscus.