The invention relates to compositions and methods for preventing, treating, or managing osteoporosis or conditions which are characterized by increased bone resorption, comprising administration of a prophylactically and therapeutically effective amount of Cissus quadrangularis plant or extracts thereof to a mammal in need of such therapy. Preferably the mammal is human and the compositions comprise of single extract or a combination of extracts thereof. The present invention further relates to extracts which are isolated from different parts of Cissus quadrangularis plant, the preparation of such extracts, the medicaments containing said extracts, and the use of these extracts and constituents for the preparation of a medicament. The present invention also relates to the process for preparing the extracts from various parts of Cissus quadrangularis plant.