thank you prof, please does location have effect on the phytochemical ability

Hi Wasiu, YES, location can have profound impact on the metabolites a plant produces. Think simply tomatoes - depending where they grow they will have a different taste. In case of medicinal plants like Centella location is highly important. Many traditional medicinal systems recognize this and often give the same species different vernacular names depending on where the plant grows. Also, healers often go to great lengths to collect always from the same locations, to make sure that they get plants with consistent properties. This is also where harvest time comes in. Many plants change their compound composition during the seasons, and only show efficacy part of the time. Last, the location is an important aspect of climate change - when plants migrate their compound composition might also change, which could make them more or less efficacious, and/or more or less toxic.

The exact meaning of "accession", is the act of rising to an important position or a higher level. So in centella asiatica its exclusively means Position. Soil, temperature, climatic conditions, humidity all have direct impact on the Phytochemistry of any plant. 

Thank you for the contribution and guidance