Alpha Shield Bisabolol, Melaleuca alternifolia leaf oil.Bisabolol (and) Melaleuca Alternifolia Leaf Oil. ALPHASHIELD is a natural preservative, dermo-purifier and anti-irritant agent. This active, 100% natural, biodegradable ingredient possesses potent germicidal action, proven by tests, quickly eliminating (within one minute) 99.99% of germs (gram positive and negative bacteria, in addition to fungi).