According to Cabrera, green tea contains gallic acid, a powerful antioxidant in its own right. It also contains carotenoids, tocopherols, ascorbic acid (vitamin C) and minerals such as chromium, manganese, selenium, zinc and certain phytochemical compounds.
1. forceful, strong. Powerful, mighty, potent suggest great force or strength. Powerful suggests capability of exerting great force or overcoming strong resistance: a powerful machine like a bulldozer. Mighty, now chiefly rhetorical, implies uncommon or overwhelming strength of power: a mighty army.
Some kind of definition is necessary for speak truth to power, and truth to power. I assume the latter can be spoken, heard, conveyed or done with in other ways. I also assume one can hear or see a truth to power where none is intended. I put some citations from this millennium on Citations:speak truth to power.