The valorisation of vegetable waste from various economic activities, becoming one of the major concerns in many countries around the world. They are trying to develop green and sustainable methodologies for utilization of these important sources of bioactive components that belong to various groups of natural compounds. A special place in the range of biologically active natural compounds is occupied by diterpenoids and triterpenoids. The products or active principles obtained from them are widely used in perfumery, cosmetics, agriculture, tobacco industry, pharmaceuticals and other fields of human activity. Researchers from the Institute of Chemistry of Moldova have accumulated a rich experience regarding the isolation and chemical transformation of terpene compounds from vegetable waste, including local ones. Using known or new processes, here were isolated diterpenoids – (-)-sclareol from concrete of Clary sage (Salvia sclarea L.), ent-trachilobanoic and ent-kaurenoic acids from sunflower wastes and triterpenoids – ursolic and oleanolic acids from lavender wastes and apple pomace. The research was focused on the development of original methods for the preparation of new functionalized bicyclic nitrogen-containing diterpenoids based on the available natural diterpenoid – sclareol and designing of natural chiral molecules of interest to the pharmaceutical industry. Bicyclic di- and sesquiterpenoid functionalization was performed both in the lateral chain and in the C-7 position of the B cycle, producing lactams and derivatives containing an amino group, or azine, hydrazide, dihydrazide and guanidine fragments, as well as heterocyclic units. Experimental work included extraction methods such as Soxhlet or ultrasound-assisted, column chromatographic separations, thin layer chromatography (TLC), gas chromatography-mass spectrometry (GCMS) and high-performance liquid chromatography (HPLC) analyses. Chemical transformations of starting diand triterpenoids were performed by conventional and non-conventional (microwave, photochemical, electrochemical) methods of synthesis. The structures of synthetized compounds were proved by spectral methods (IR and NMR), mass-spectrometry and X-rays analysis on single crystal. As a result of the research, based on the mentioned compounds, dozens of natural analogs, odorous or biologically active compounds were synthesized. A series of over 50 newly obtained substances was subjected to biological testing, of which 10 showed pronounced antifungal and antibacterial activity, 2 amides showed pronounced antioxidant activity, and two derivatives with guanidine fragment showed high antitumor activity.