## 1 Introduction  
The _Pabularia_ Lindl.--Computational and Experimental Investigations (P.A.A.) is a widely  
**Keywords:**_Prangos papularia_ Lindl. ; volatile oil; PTP-1B; osthole; 5-pentylcyclohexa-1,3-diene; antidiabetic activity +
Footnote †: journal: Journal of chemical and chemical biology  
## 1 Introduction  
Diabetes, or diabetes mellitus, is a chronic metabolic disease associated with high blood sugar levels over a prolonged period [1]. In 2017, according to the International Diabetes Federation report, approximately 425 million adults (20-79 years) had diabetes worldwide with 3.2 to 5.0 million deaths from the disease [2]. Unfortunately, these numbers are gradually increasing in most countries. From ancient times, humans have used medicinal plants for the prevention and the therapy of diabetes mellitus. Medicinal plants serve as natural sources for the discovery of compounds with antidiabetic activities. In this relation, Tajikstan has a rich flora with around 4550 species of higher plants that represent great interest for the discovery of alternative medications for the treatment of diabetes [3]. Tajikistan is known for its diversity of environmental conditions, including climate, high altitudes, mountainous soil and minerals, and a relatively large number of sunny days per year, factors that can affect plant development as well as biosynthesis and accumulation of secondary metabolites [4; 5]. Essential oils have applications in medicine, pharmaceutical, food, and cosmetic industries. They possess possible health benefits with antioxidant, antimicrobial, antitumor, anticarcinogenic, anti-inflammatory, anti-atherosclerosis, antimutagenic, antiplatelet aggregation, and angiogenesis-inhibitory activities. Therefore, extensive research has been directed toward the use of medicinal plants to control diabetes mellitus and its complications [6]. PTP-1B (protein-tyrosine phosphatase 1B) belongs to the protein tyrosine phosphatase (PTP) family. It is also known as tyrosine-protein phosphatase non-receptor type 1 that is encoded by the _PTPN1_ gene [7; 8]. PTP-1B is localized on the cytoplasmic face of the endoplasmic reticulum and contains the essential catalytic cysteine [9]. The PTP-1B enzyme catalyzes the hydrolysis of phosphotyrosine from specific proteins [10]. PTP-1B is considered to be a promising potential therapeutic target for treatment of various diseases, including diabetes, obesity, and cancer [11]. It inactivates the insulin signal transduction cascade by dephosphoritating phosphotyrosine residues in the insulin-signaling pathway [12]. Natural, synthetic, as well as semi-synthetic compounds have shown prominent antidiabetic activities by inhibiting PTP-1B activity [13]. _Prangos papularia_ Lindl., a member of the Apiaceae, is a widely distributed herb up to 150 cm high with a thick cylindrical root and has large reserves in Tajikistan [14]. _P. papularia_, locally known as \"Yugan\", is a well-known species of the genus in Tajikistan. It typically grows in mountainous areas and limestone slopes at altitudes 780 to 3600 m above sea level [15]. Its roots and fruits are valued in Tajik traditional medicine and are widely used as general tonics as well as for treatment of vitiligo [4; 15]. _P. papularia_ has been used to treat leukoplakia, digestive disorders, scars, and bleeding [16]. The root extracts of _P. papularia_ have been examined for cytotoxic activity; the dichloromethane extract of _P. papularia_ roots demonstrated notable cytotoxicity on the HeLa carcinoma cell line [17]. _P. fernacea_ root is used as an effective wound healing agent in traditional medicine of the western north of Iran [18]. Members of the _Prangos_ genus are natural sources of phytochemicals, including coumarins and terpenoids. Individual isolated pure compounds such as osthole and isomperatorin showed the highest inhibitory potency against the growth of human carcinoma cell lines. Osthole exhibited the greatest cytotoxicity and was found to induce apoptosis in PC-3, H1299, and SKNMC cells at low micromolar concentrations.