Study on chemical constituents in stems of Dendrobium nobile Nitrogeous chemical constituents from Tinosporae Radix Chemical studies on root bark of Lycium chinense Study on chemical constituents from roots and rhizomes of Acorus tatarinowii Chemical constituents from stems and leaves of Humulus scandens Chemical constituents from twigs of Myricaria bracteata Chemical constituents in root barks of Lycium chinense