## 1 Introduction  
Obesity is a serious medical concern in today's world and characterized by excess fat accumulation which is not only an aesthetic problem but also an underlying cause of several diseases such as cardiovascular diseases, different types of cancer, organ failures, and diabetes [1, 2]. Excess accumulation of body fat occurs through elevated levels of adipose tissue formation, which is a result of adipogenic differentiation of adipogenic progenitor stem cells. However, recent studies clearly showed that adipose tissue, and adipogenesis thereof, is not only linked to obesity but also several other diseases [3, 4]. The close and complex regulatory relations between white and brown adipose tissues, which are the most abundant distinct adipose tissues in the human body, are considered to be the reason behind the obesity onset and progression [4]. Adipose tissue consists of distinct tissues in addition to white and brown adipose tissues, such as bone-marrow adipose tissue. The differentiation capabilities and roles they take in various mechanisms in homeostasis make human mesenchymal stem cells promising targets for regenerative medicine and have been utilized in several studies against diabetes, cardiovascular diseases, and osteoarthritis [5]. The differential tendencies towards adipogenesis in progenitor cells occurs not only in adipose tissue but in other parts of the body as well where mesenchymal stromal cells are present. For example, osteoporosis is a very common bone disorder where bone-marrow cells tend to differentiate into adipocytes rather than osteoblasts under the influence of several effectors including obesity [6]. In bone tissue, activation of the intracellular mechanisms that lead to stimulation of adipogenic differentiation elevates the adipocyte count and deteriorates the balance between bone formation and bone adipose tissue [7]. In addition, studies showed that differentiation of stromal cells in one part of the body affects the other progenitor cells. For instance, increased adipogenic differentiation of bone-marrow stromal cells induce changes in overall body adiposity through elevated adipogenesis in adipose tissue progenitor cells [8; 9]. Mesenchymal stem cells are one of the widely studied in vitro models for studies targeting differential regulation of adipogenic progenitor cells to develop novel strategies against obesity and osteoporosis as well as developing regenerative medicine [4]. Peroxisome proliferatorator-activated receptor (PPAR) is the main regulatory protein responsible for the onset of adipogenesis [10]. Several other upstream and downstream effectors of PPAR are involved in the stimulation of adipogenic differentiation and adipocyte maturation of MSCs. These effectors include SREBPP1 and C/EBP\(\alpha\)[10; 11]. On the other hand, Wnt/\(\beta\)-catenin signaling, the activation of which is vital for osteogenic differentiation, is suppressed during adipogenesis in order to tilt MSC differentiation balance towards adipogenesis [12]. Recently, several studies focused on regulation of MSC differentiation: inhibiting the adipogenesis while enhancing osteoblastsiensis to prevent or treat obesity-linked complications [13; 14]. There are studies addressing obesity using MSCs derived from adipose tissue [5]. However, utilizing hBM-MSCs in order to regulate adipogenesis in relation to osteoblastsiensis is another aspect of the obesity-linked osteoporosis which was aimed to be achieved by the current study. Lolololide is a common monotrepenoid hydroxyl lactone mainly found in algae, although it is ubiquitously present in other plants as an alleochemical response modulator for plant-to-plant interactions [15]. Studies reported bioactive properties for lololide such as antioxidant, antiviral, anticancer and hair promoting activities [16; 17]. Loliolide has been shown to inhibit adipogenic differentiation of 3T3-L1 murine pre-adipocytes [18] and decrease the adiposity of liver in high-fat diet in vivo models [19].