-1- ABSTRACT Pterospermum javanicum Jungh. (Bayur) is a species belongs to the Pterospermum genera (Malvaceae). Several species of Pterospermum had been reported for their ethnobotanical usage, but the studies about ethnobotany information of Bayur and its secondary metabolite compounds were still limited which have been published. This study aimed to observe the ethnobotanical usage of Bayur and to examine the phytochemical contents of the acetone extract of Bayur flower from West Lombok. The ethnobotany information of Bayur was obtained through interviews with local people and more information on the ethnobotanical records of P. javanicum (Bayur) was conducted by reviewing the scientific literature. The chemical compounds of Bayur flower were analysed by the GC-MS method. The results revealed that Bayur was used by the Sasak community around Gunung Rinjani National Park West Lombok for various purposes, such as traditional medicines, beverages, rigging, and building material. The phytochemical analysis showed that the acetone extract of Bayur flower from West Lombok contained 38 identified chemical components, representing 93.78% of the total compounds. The major contents of them were Lupeyl acetate (10.68%), p-n-Amylphenol (8.16%), Lauric acid (7.31%), N-(Methyl-d2)- Aniline (5,82%), and Pentanal (5.07%). This report was the first publication about the phytochemical contents of Bayur flower. It is expected that this study gives further information on the potentials of Bayur, especially about its secondary metabolite to support and prove the truth of the cultural concept of society in utilizing Bayur as a medicinal plant. Keywords: Bayur Flower, Ethnobotany, GC-MS Analysis, Pterospermum javanicum Research Article Ethnobotanical and Phytochemical Study of Bayur (Pterospermum javanicum Jungh.) on Sasak Tribe around Mount Rinjani National Park, West Lombok as a Conservation Effort Putri Sri Andila 1 *, Tri Warseno 1 , I Putu Agus Hendra Wibawa 1 , I Gede Tirta 1 1) Bali Botanic Gardens, Research Center for Plant Conservation and Botanic Gardens, Indonesian Institute of Sciences (LIPI) Jl. Kebun Raya, Candikuning, Baturiti, Tabanan 82191, Bali, Indonesia. Tel.: +62-368-2033211 * Corresponding author, email: Putribot11@gmail.com Submitted: 01 November 2020; Accepted: 08 March 2021; Published online: 01 April 2021 Journal of Tropical Biodiversity and Biotechnology Volume 06, Issue 01 (2021): jtbb61008 DOI: 10.22146/jtbb.61008 INTRODUCTION Malvaceae is a family of the flowering plant which is comprised of around 85 genera and 1500 species, distributed widely in the tropical and temperate region (Rahman & Gondha 2014) It has been a long time known that several species of Malvaceae have been reported as traditional medicines in many countries to treat various human diseases and disorder (Al Muqarrabun & Ahmat 2015). In India, Pterospermum acerifolium L. Willd with the local name ‘Muchukunda' traditionally was used to treat for blood Copyright: © 2021, J. Tropical Biodiversity Biotechnology (CC BY-SA 4.0)