Sclareolide, a natural product with bioactive and fragrant properties, is not only utilized in the food, healthcare, and cosmetics industries but also serves as a precursor for the production of ambroxide and some bioactive compounds. Currently, there are three primary methods for producing sclareolide: direct extraction from plants, chemical synthesis using sclareol as a precursor, and the biotransformation of sclareol. Here, we established a platform for producing sclareolide through a modular coculture system with Saccharomyces cerevisiae and Cryptococcus albidus ATCC 20918. S. cerevisiae was engineered for de novo sclareol biosynthesis from glucose, while C. albidus enabled the production of sclareolide via sclareol biotransformation. To enhance the supply of sclareol, a recombinant yeast strain was constructed through metabolic engineering to produce 536.2 mg/L of sclareol. Further improvement of the coculture system for sclareolide production was achieved by incorporating Triton X-100 facilitated intermediate permeability, inoculation proportion adjustment, and culture temperature optimization. These refinements culminated in a sclareolide yield of 626.3 mg/L. This study presents a novel streamlined and efficient approach for sclareolide preparation, showcasing the potential of the microbial consortium in sustainable bioproduction.

BACKGROUND: Inflammation-induced intestinal barrier dysfunction is not only a pathological feature of Crohn\'s disease (CD) but also an important therapeutic target. Sclareol (SCL) is a nontoxic natural plant compound with anti-inflammatory effect, but its role in CD has not been established.
METHODS: In vivo studies of mice with TNBS-induced colitis were carried out to evaluate the effects of SCL on CD-like colitis and intestinal barrier function. In vitro, a TNF-α-induced colonic organoid model was established to test the direct effect of SCL on inflammation-induced intestinal barrier injure and inflammatory response. The Nrf2/NF-κB/MLCK signalling was analysed to explore the mechanism of SCL.
RESULTS: In vivo, SCL largely alleviated the colitis in TNBS mice, as evidenced by improvements in the weight loss, colitis symptoms, endoscopic score, macroscopic histological score, and histological inflammation score. Moreover, SCL significantly improved intestinal barrier dysfunction, manifested as reduced intestinal permeability and decreased intestinal bacterial translocation in TNBS mice. Importantly, SCL antagonised the intestinal mucosal inflammation while protecting tight junctions in TNBS mice. In vitro, SCL largely depressed pro-inflammatory cytokines levels and improved intestinal epithelial permeability in a TNF-α-induced colonic organoid model. In the context of CD, the protective effects of SCL against inflammation and intestinal barrier damage are at least partially results from the Nrf2 signalling activation and the NF-κB/MLCK signalling inhibition.
CONCLUSIONS: SCL improved intestinal barrier dysfunction and alleviated CD-like colitis, possibly through modulation of Nrf2/NF-κB/MLCK signalling. In view of SCL\'s safety profile, there is hope that it will be useful in the clinic.

Objectives: Sclareol (SCL) is a natural diterpene with anti-inflammation and antioxidant properties. This study aimed to assess the hepatoprotective effects of SCL in diabetic mice. Methods: SCL (10 mg/kg) was administered intragastrically to C57BL/6 mice with streptozotocin-induced diabetes daily for 5 weeks to evaluate its beneficial effects in liver injury. Body and liver weight and blood glucose levels were measured. Liver histopathology, fibrosis, and lipid accumulation were evaluated using hematoxylin and eosin, Masson\'s trichrome, and Oil Red O staining, respectively. Serum hepatic enzyme and lipid levels were measured using an automatic biochemical analyzer. Hepatocellular apoptosis was measured using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Oxidative stress markers and reactive oxygen species (ROS) were measured using appropriate assay kits. The effects of sclareol on inflammation and lipid metabolism was evaluated by enzyme-linked immunosorbent assay (ELISA), immunohistochemical analysis, and Western blot assays. Results: SCL significantly decreased serum liver enzymes and lipids levels, and alleviated adipogenesis and fibrosis. Moreover, the protein levels of acetyl-CoA carboxylase and sterol response element-binding protein 1 were downregulated, whereas the expression of carnitine palmitoyl transferase 1 was upregulated. SCL increased the antioxidant activity, and decreased ROS levels. SCL alleviated hepatic mitochondrial damage. Furthermore, SCL inhibited Kupffer cell infiltration and reduced serum inflammatory cytokine levels. SCL significantly downregulated the protein expression of nuclear factor-kappa B (NF-κB) P65, NOD-like receptor protein 3 (NLRP3), caspase 1, and interleukin-1β. Conclusions: Our findings suggest that SCL improves diabetes-induced liver injury by alleviating the NF-κB/NLRP3-mediated inflammation and lipid metabolism disorder.

Microbial endophytes are known as versatile producers of useful metabolites, which have extensive applications in pharmacy, fragrance, agriculture and food. This study aims to screen sclareol-biotransforming microorganisms from Salvia sclarea, an untapped source of diverse endophytes. In this study, 50 culturable endophytes were isolated from S. sclarea grown in Xinjiang using sclareol as the sole carbon source and screened for their potential to transform sclareol into analogues. A fungal endophyte, identified as the generally recognized as safe (GRAS) strain Aspergillus tubingensis, can produce labd-14-ene-3β,8α,13β-triol and 8α,13β-dihydroxylabd-14-en-3-one from sclareol, involving hydroxylation and carbonylation at the C3 site. Structures of the two metabolites were elucidated by HR-ESI-MS and NMR analysis. S. sclarea was proven to be a good source of endophytes that are prospective producers of secondary metabolites with valuable chemical and biological properties. This study is the first report regarding the isolation of endophytes from S. sclarea.

Liver fibrosis is a key global health care burden. Sclareol, isolated from Salvia sclarea, possesses various biological activities. Its effect on liver fibrosis remains unknown. This study was proposed to evaluate the antifibrotic activity of sclareol (SCL) and explore its underlying mechanisms. Stimulated hepatic stellate cells served as an in vitro liver fibrosis model. The expression of fibrotic markers was assessed by western blot and real-time PCR. Two classical animal models, bile duct-ligated rats and carbon tetrachloride-treated mice, were utilized for the in vivo experiments. The liver function and fibrosis degree were determined by serum biochemical and histopathological analyses. VEGFR2 SUMOylation was analyzed using coimmunoprecipitation assay. Our results indicated that SCL treatment restricted the profibrotic propensity of activated HSCs. In fibrotic rodents, SCL administration alleviated hepatic injury and reduced collagen accumulation. Mechanistic studies indicated that SCL downregulated the protein level of SENP1 and enhanced VEGFR2 SUMOylation in LX-2 cells, which affected its intracellular trafficking. Blockade of the interaction between VEGFR2 and STAT3 was observed, resulting in the suppression of downstream STAT3 phosphorylation. Our findings demonstrated that SCL has therapeutic efficacy against liver fibrosis through mediating VEGFR2 SUMOylation, suggesting that SCL may be a potential candidate compound for its treatment.

In this study, a newly isolated strain Filobasidium magnum JD1025 was investigated for its production of sclareolide, which was verified to be a valuable raw material in various industrial fields. Together with a comprehensive analysis of the genome sequence, effective fermentation method to convert sclareol to sclareolide via the isolated strain was explored and optimized by taking the selected co-solvent and nitrogen source into account. The results showed that the final conversion rate could be achieved at 88.79 ± 1.06% with the initial sclareol concentration of 30 g·L-1 after 72 h in baffled flask. The corresponding yield concentration of sclareolide was 21.62 ± 0.26 g·L-1 and the conversion rate per unit thallus attained to 6.11 ± 0.06 % g-1·L-1. Overall, the current study suggested a valid method for the application of Filobasidium magnum JD1025 as bio-transformer to produce sclareolide from sclareol.

Sclareol, a diterpene alcohol isolated from the herbal and flavor plant clary sage (Salvia sclarea L.), is far-famed as the predominant ingredient in the refined oil of Salvia sclarea (L.). The empirical medicine of Salvia sclarea L. focused on various diseases, such as arthritis, oral inflammation, digestive system diseases, whereas the sclareol possessed more extensive and characteristic bioactivities, including anti-tumor, anti-inflammation and anti-pathogenic microbes, even anti-diabetes and hypertension. However, there is a deficiency of literature to integrate and illuminate the pharmacological attributes of sclareol based on well-documented investigations. Interestingly, sclareol has been recently considered as the potential candidate against COVID-19 and Parkinson\'s disease. Accordingly, the bioactive attributes of sclareol in cancer, inflammation, even pharmacochemistry and delivery systems are reviewed for comprehensively dissecting its potential application in medicine.

Chronic inflammation plays an important role in hypertensive heart failure. Suppressing angiotensin II (Ang II)-induced cardiac inflammation may contribute to the treatment of hypertension-associated heart failure. Sclareol, a natural product initially isolated from the leaves and flowers of Salvia sclarea, possesses antiinflammatory and immune-regulation activity in various systems. However, its effect on Ang II-induced cardiac remodeling remains unknown. In this study, we have explored the potential effects of sclareol on Ang II-induced heart failure. In vivo experiments were conducted in mice with Ang II-pump infusion for 28 days. Sclareol administration at 5 mg·kg-1 ·d-1 significantly reduced the expression of myocardial injury markers. Sclareol also exerts protective effects against Ang II-induced cardiac dysfunction in mice which is associated with alleviated cardiac inflammation and fibrosis. Transcriptome analysis revealed that inhibition of the Ang II-activated mitogen-activated protein kinase (MAPK) pathway contributed to the protective effect of sclareol. Sclareol inhibits Ang II-activated MAPKs pathway to reduce inflammatory response in mouse hearts and cultured cardiomyocytes. Blockage of MAPKs in cardiomyocytes abolished the antiinflammatory effects of sclareol. In conclusion, we show that sclareol protects hearts against Ang II-induced injuries through inhibiting MAPK-mediated inflammation, indicating the potential use of sclareol in the prevention of hypertensive heart failure.

Sclareol glycol is a key starting material with significant market interest for synthesizing high-value ambroxide, a sustainable substitute for ambergris in high-end fragrances. Sclareol glycol can be obtained by biotransformation of sclareol, a labdane-type diterpene, using Hyphozyma roseonigra. However, the pathway and mechanism of sclareol glycol biosynthesis remain unclear. In this study, the dynamic time course of sclareol biotransformation was explored by resting cell assays and several intermediates produced during biotransformation were detected. The results show that (1) sclareol glycol and sclareolide are not interconverted and are potentially synthesized via different metabolic pathways and (2) several putative intermediates resulting from biotransformation are featured with a labdane carbon backbone, including isomerized and oxidized analogues. A plausible transformation pathway of sclareol in H. roseonigra was proposed based on detected metabolites. This study sheds light on the biosynthetic mechanism of sclareol glycol and paves a way for the future biotechnological production of this promising compound.

Diabetic nephropathy (DN) represents the most serious complication of diabetes. Previous studies have shown that the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) are linked to inflammation in the development of DN. Sclareol, a natural diterpene compound, has beneficial effects on inflammation. Thus, we hypothesized that sclareol might prevent DN via anti-inflammatory actions. This study aimed to investigate the actions of sclareol in the progression of DN, and explored the related molecular mechanism. Sclareol treatment significantly alleviated renal dysfunction, fibrosis, and inflammatory cytokine levels in a dose-dependent manner in diabetic mice. Moreover, sclareol inhibited the activations of MAPKs and NF-κB in diabetic kidney tissues. The therapeutic effects of sclareol were confirmed under high levels of glucose in SV40 cells, and sclareol prevented high glucose-induced fibrosis and inflammatory responses, which was largely driven by MAPKs and NF-κB inhibitions. In particular, MAPKs inhibitors mixture could suppress the NF-κB pathway and release of inflammatory cytokines that sclareol was involved in. In conclusion, sclareol has benefits for diabetes-induced renal dysfunction, which was partially associated with amelioration of fibrosis and inflammation via mediation of the MAPK/NF-κB signaling pathway. Sclareol may be a promising agent for preventing the progression of DN.