###### Abstract
In 1981, dammarane-type saponin components (panaxadiol and 2\(\alpha\)-hydroxypanaxadiol) were first isolated from _G. pentaphyllum_[8]. These compounds bear structural similarities to ginsenosides and have garnered considerable attention from researchers. Since then, numerous studies have yielded significant findings regarding the principal chemical constituents of _G. pentaphyllum_, particularly concerning its saponin compounds. To date, over 200 distinct saponins have been isolated from this plant; notably, about 25% share structures akin to those found in ginsenosides [7]. Importantly, gypenosides III, IV, VIII, XIII, I, and A-AH possess identical structures to their counterparts among ginsenosides Rb1, Rb3, Rd, F2, K, and Rg3, respectively, and they have thus been identified as equivalent substances under different nomenclatures [9]. Due to the high demand for ginsenosides in the pharmaceutical industry, gypenosides can be converted into ginsenosides through bacterial enzyme engineering technology. This has led to increased interest in _G. pentaphyllum_ within medicinal plant research [10]. Furthermore, the genus _Gynostemma_ is the only taxon besides _Panax_ that contains ginsenosides. It offers numerous advantages such as wide distribution, rapid growth, and a higher saponin content, rendering it valuable for both practical applications and academic research [11; 12; 13]. However, the type and content of gypenosides are often closely associated with the geographical distribution of _G. pentaphyllum_[14]. Consequently, investigating the content of gypenosides and their biosynthetic genes across different regions inhabited by _G. pentaphyllum_ can not only elucidate the molecular mechanisms underlying gypenoside formation, but also provide comprehensive theoretical support for developing high-quality traditional Chinese medicine. Currently, significant progress has been made in studies concerning the biosynthesis pathway of ginsenosides. However, research on the biosynthesis of gypenosides remains limited. Previous investigations have demonstrated that saponins derived from both _G. pentaphyllum_ and _Panax ginseng_ exhibit structural similarities and fall under tetracyclic triterpenoid saponins [3; 12]. The biosynthetic pathway comprises three primary stages: (1) Initial stage--isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP) are synthesized. (2) Formation stage of triterpen skeleton--IPP and DMAPP molecules undergo successive catalysis by geranyl pyrophosphate synthase (GPPS), farnesyl pyrophosphate synthase (FPS), squalene synthase (SS), and squalene epoxidase (SE) to yield 2,3-oxidosqualene. Subsequently, 2,3-oxidosqualene can generate various types of triterpenoid skeletons under the influence of distinct oxidosqualene cyclases (OSCs). (3) Modification stage of triterpenoid skeleton--under the influence of cytochrome P450, glycosyltransferases, acyltransferases, and other modifying enzymes, various triterpen saponin end products are generated through oxidation, glycosylation, acylation, and other chemical modifications of the triterpen skeletons [11]. In this process, the cyclization of 2,3-oxidosqualene by an OSC enzyme represents a critical initial step in the biosynthesis of plant triterpenoid saponins. This step is pivotal in determining the diversity of triterpenoid products and has the potential to yield over 100 distinct triterpen saponin skeletons [15; 16]. The OSC (oxidosqualene cyclase) is a key enzyme within the biosynthetic pathway for sterols and triterpenes in plants. Based on intermediate structures formed during substrate binding and folding, namely chair-chair-chair (CCC) and chair-bouat-chair (CBC) conformations, sterol and triterpene compounds are synthesized. As a super gene family in plants, the _OSC_ family members exhibit highly conserved sequences such as DCTAE and QW (QXXXXXW) [17].