Green Extraction of Plant Materials Using Supercritical CO2: Insights into Methods, Analysis, and Bioactivity

In recent years, the supercritical CO2 extraction method has gained attention due to its use of environmentally friendly, non-toxic solvents, ability to operate at lower temperatures that do not cause the degradation of bioactive compounds, and capacity for rapid extraction. This method is particularly notable for isolating bioactive compounds from plants. The extracts obtained have shown superior properties due to their activity against diseases such as cancer, which is one of the leading causes of death worldwide. The aim of this study is to provide an in-depth understanding of the supercritical CO2 extraction method, as well as to discuss its advantages and disadvantages. Furthermore, the study includes specific data on various plant materials, detailing the following parameters: plant name and region, bioactive compounds or compound classes, extraction temperature (°C), pressure (bar), time (minutes), co-solvent used, and flow rate. Additionally, this study covers extensive research on the isolation of bioactive compounds and the efficacy of the obtained extracts against cancer.

Antioxidant, Anti-Inflammation, and Melanogenesis Inhibition of Sang 5 CMU Rice (Oryza sativa) Byproduct for Cosmetic Applications

Prolonged exposure to environmental oxidative stress can result in visible signs of skin aging such as wrinkles, hyperpigmentation, and thinning of the skin. Oryza sativa variety Sang 5 CMU, an inbred rice cultivar from northern Thailand, contains phenolic and flavonoid compounds in its bran and husk portions that are known for their natural antioxidant properties. In this study, we evaluated the cosmetic properties of crude extracts from rice bran and husk of Sang 5 CMU, focusing on antioxidant, anti-inflammatory, anti-melanogenesis, and collagen-regulating properties. Our findings suggest that both extracts possess antioxidant potential against DPPH, ABTS radicals, and metal ions. Additionally, they could downregulate TBARS levels from 125% to 100% of the control, approximately, while increasing the expression of genes related to the NRF2-mediated antioxidant pathway, such as NRF2 and HO-1, in H2O2-induced human fibroblast cells. Notably, rice bran and husk extracts could increase mRNA levels of HO-1 more greatly than the standard L-ascorbic acid, by about 1.29 and 1.07 times, respectively. Furthermore, the crude extracts exhibited anti-inflammatory activity by suppressing nitric oxide production in both mouse macrophage and human fibroblast cells. Specifically, the bran and husk extracts inhibited the gene expression of the inflammatory cytokine IL-6 in LPS-induced inflammation in fibroblasts. Moreover, both extracts demonstrated potential for inhibiting melanin production and intracellular tyrosinase activity in human melanoma cells by decreasing the expression of the transcription factor MITF and the pigmentary genes TYR, TRP-1, and DCT. They also exhibit collagen-stimulating effects by reducing MMP-2 expression in H2O2-induced fibroblasts from 135% to 80% of the control, approximately, and increasing the gene associated with type I collagen production, COL1A1. Overall, the rice bran and husk extracts of Sang 5 CMU showed promise as effective natural ingredients for cosmetic applications.

Hair Growth Promotion and Anti-Hair Loss Effects of By-Products Arabica Coffee Pulp Extracts Using Supercritical Fluid Extraction

Coffee has been a common ingredient in many traditional hair loss remedies, but limited scientific evidence supports its use, particularly in coffee pulp. Androgenetic alopecia (AGA) is caused by androgens, inflammation, and oxidative stress. In the present study, supercritical fluid extraction (SFE) was used under various conditions to obtain six coffee pulp extracts. The SFE-4 extract, using 50% (v/v) ethanol as a co-solvent at conditions of 100 °C and 500 bars for 30 min, exhibited the highest phenolic, flavonoid, and caffeine contents. Additionally, the SFE-4 extract increased the migration and cell proliferation of HFDPCs (human hair follicle dermal papilla cells), which control hair cycle regulation, and had scavenging effects on ABTS and DPPH radicals. Additionally, the SFE-4 extract showed potassium ion channel opener activity in HFDPCs, as well as a stimulation effect on the enzyme matrix metalloproteinase-2 (MMP-2) (28.53 ± 1.08% of control), which may be related to the vascular endothelial growth factor (VEGF) gene upregulation. In human prostate cancer cells (DU-145) and HFDPC cells, the SFE-4 extract significantly decreased the expression of SRD5A1, SRD5A2, and SRD5A3, an essential pathway involved in AGA. Hair growth factor genes in the Wnt/-catenin (CTNNB1) and Sonic Hedgehog (SHH, SMO, and GLI1) pathways could be significantly activated by the SFE-4 extract. These results imply that employing SFE in coffee pulp extraction could help AGA treatment by preventing hair loss and promoting hair growth pathways. This would help small coffee producers gain economic empowerment and ensure the long-term sustainability of agricultural waste utilization.

Simultaneous determination of four active compounds in Centella asiatica by supramolecular solvent-based extraction coupled with high performance liquid chromatography-tandem mass spectrometry

In the present study, a new and rapid method for determining four bioactive compounds of Centella asiatica (C. asiatica) in herbs was developed based on high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). Supramolecular solvent (SUPRAS), formed by n-hexanol, tetrahydrofuran (THF) and water, was used for extracting madecassoside (MS), asiaticoside (AS), asiatic acid (AA) and madecassic acid (MA) from herbs. The sample was extracted with 4 mL of SUPRAS for 5 min. Then centrifugation was performed for phase separation followed by direct analysis by HPLC-MS/MS. Driving forces for the extraction of herbs in the SUPRAS involved both dispersion and hydrogen bond interactions. The effect of the parameters, including compounds of supramolecular solvents, dosage and vortex time, on the extraction efficiency was investigated. The recoveries were carried out at three levels with spiked samples and in the range of 91.6%-99.9%, with relative standard deviations between 1.7%-7.9%. The novel SUPRAS method, coupled with HPLC-MS/MS, was proved to be efficiency, green, and sensitive. It was applied for determination of four target compounds in herbs.

Wound Healing Effect of Supercritical Carbon Dioxide Datura metel L. Leaves Extracts: An In Vitro Study of Anti-Inflammation, Cell Migration, MMP-2 Inhibition, and the Modulation of the Sonic Hedgehog Pathway in Human Fibroblasts

Datura metel L. (thorn apple) has been used in Thai folk wisdom for wound care. In this study, we chose supercritical carbon dioxide extraction (scCO₂) to develop crude extraction from the leaves of the thorn apple. The phytochemical profiles were observed using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). The biological activities of D. metel were performed through antioxidant assays, anti-inflammation based on the Griess reaction, the migration assay, the expression of matrix metalloproteinase-2 (MMP-2), and regulatory genes in fibroblasts. Dm1 and Dm2 extracts were obtained from scCO₂ procedures at different pressures of 300 and 500 bar, respectively. Bioactive compounds, including farnesyl acetone, schisanhenol B, and loliolide, were identified in both extracts. The antioxidant properties of both D. metel extracts were comparable to those of l-ascorbic acid in hydrogen peroxide-induced fibroblasts with no significant difference. Additionally, Dm1 and Dm2 significantly inhibited the nitrite production levels of 1.23 ± 0.19 and 1.52 ± 0.05 μM, respectively, against the lipopolysaccharide-treated group (3.82 ± 0.39 μM). Interestingly, Dm1 obviously demonstrated the percentage of wound closure with 58.46 ± 7.61 and 82.62 ± 6.66% after 36 and 48 h of treatment, which were comparable to the commercial deproteinized dialysate from the calf blood extract. Moreover, both extracts were comparable to l-ascorbic acid treatment in their ability to suppress the expression of MMP-2: an enzyme that breaks down collagen. The gene expressions of SHH, SMO, and GLI1 that control the sonic hedgehog pathway were also clearly upregulated by Dm1. Consequently, the scCO₂ technique could be applied in D. metel extraction and contribute to potentially effective wound closure.

A review of pharmacokinetic and pharmacological properties of asiaticoside, a major active constituent of Centella asiatica (L.) Urb

ETHNOPHARMACOLOGICAL RELEVANCE

Centella asiatica (L.) Urb., a potential medicinal plant, is widely used in orient traditional medicine. Its major active constituents include asiaticoside (AS), madecassoside (MS), asiatic acid and madecassic acid. Thereinto, AS is a pentacyclic triterpenoid saponin with a variety of pharmacological effects including antitumor, neuroprotective and wound healing effects.

AIM OF THE STUDY

In this review, we summarize the pharmacokinetics, safety and pharmacological properties of AS.

MATERIALS AND METHODS

We gathered information about AS from articles published up to 2022 and listed in Google scholar, PubMed, Web of Science, Elsevier, and similar databases. The keywords used in our search included "asiaticoside", "Centella asiatica", "pharmacokinetics", "nerve", "cancer", "skin", etc. RESULTS: AS appeared to degrade through a first-order reaction and had low biotoxicity. However, the pharmacokinetic properties of AS differed according to species. AS is highly blood-brain-barrier permeable without any harmful side effect. It has a variety of pharmacological effects including anti-neural inflammation and anti-cancer properties, as well as protective properties for the skin, cardiovascular system, and pulmonary system.

CONCLUSION

This review comprehensively summarized current information regarding the pharmacokinetic and pharmacological properties of AS, and supported the pharmaceutical value of this compound. Future research should focus on improving bioavailability of AS and conducting clinical assessment.

In Vitro and In Vivo Regulation of SRD5A mRNA Expression of Supercritical Carbon Dioxide Extract from Asparagus racemosus Willd. Root as Anti-Sebum and Pore-Minimizing Active Ingredients

Oily skin from overactive sebaceous glands affects self-confidence and personality. There is report of an association between steroid 5-alpha reductase gene (SRD5A) expression and facial sebum production. There is no study of the effect of Asparagus racemosus Willd. root extract on the regulation of SRD5A mRNA expression and anti-sebum efficacy. This study extracted A. racemosus using the supercritical carbon dioxide fluid technique with ethanol and investigated its biological compounds and activities. The A. racemosus root extract had a high content of polyphenolic compounds, including quercetin, naringenin, and p-coumaric acid, and DPPH scavenging activity comparable to that of the standard L-ascorbic acid. A. racemosus root extract showed not only a significant reduction in SRD5A1 and SRD5A2 mRNA expression by about 45.45% and 90.86%, respectively, but also a reduction in the in vivo anti-sebum efficacy in male volunteers, with significantly superior percentage changes in facial sebum production and a reduction in the percentages of pore area after 15 and 30 days of treatment. It can be concluded that A. racemosus root extract with a high content of polyphenol compounds, great antioxidant effects, promising downregulation of SRD5A1 and SRD5A2, and predominant facial sebum reduction and pore-minimizing efficacy could be a candidate for an anti-sebum and pore-minimizing active ingredient to serve in functional cosmetic applications.

Antioxidation, Anti-Inflammation, and Regulation of SRD5A Gene Expression of Oryza sativa cv. Bue Bang 3 CMU Husk and Bran Extracts as Androgenetic Alopecia Molecular Treatment Substances

Androgenetic alopecia (AGA), a hair loss disorder, is a genetic predisposition to sensitive androgens, inflammation, and oxidative stress. Unfortunately, current treatments with synthetic medicines contain a restricted mechanism along with side effects, whereas the bioactive constituents of plant extracts are multifunctional, with fewer side effects. The massive amounts of rice husk and bran are agricultural wastes that may cause pollution and environmental problems. Owing to these rationales, the local rice variety, Bue Bang 3 CMU (BB3CMU), which is grown in northern Thailand, was evaluated for the valuable utilization of rice by-products, husk (BB3CMU-H) and bran (BB3CMU-RB) extracts, for AGA treatment regarding antioxidant, anti-inflammatory, anti-androgenic activities, and the characterization of bioactive compounds. Our study verified that BB3CMU-H had the highest level of polyphenols, contributing to its greater antioxidant activity. Conversely, BB3CMU-RB was the predominant source of tocopherols, resulting in better anti-androgenic activities regarding the downregulation of steroid 5α-reductase genes (SRD5A). Notably, anti-inflammation via the attenuation of nitric oxide productions was observed in BB3CMU-H (0.06 ± 0.13 μM) and BB3CMU-RB (0.13 ± 0.01 μM), which were significantly comparable to diclofenac sodium salt (0.13 ± 0.19 μM). Therefore, the combination of BB3CMU-H and BB3CMU-RB could be utilized in cosmeceutical and pharmaceutical applications for AGA patients.

High Efficiency In Vitro Wound Healing of Dictyophora indusiata Extracts via Anti-Inflammatory and Collagen Stimulating (MMP-2 Inhibition) Mechanisms

Dictyophora indusiata or Phallus indusiatus is widely used as not only traditional medicine, functional foods, but also, skin care agents. Biological activities of the fruiting body from D. indusiata were widely reported, while the studies on the application of immature bamboo mushroom extracts were limited especially in the wound healing effect. Wound healing process composed of 4 stages including hemostasis, inflammation, proliferation, and remodelling. This study divided the egg stage of bamboo mushroom into 3 parts: peel and green mixture (PGW), core (CW), and whole mushroom (WW). Then, aqueous extracts were investigated for their nucleotide sequencing, biological compound contents, and wound healing effect. The anti-inflammatory determination via the levels of cytokine releasing from macrophages, and the collagen stimulation activity on fibroblasts by matrix metalloproteinase-2 (MMP-2) inhibitory activity were determined to serve for the wound healing process promotion in the stage 2–4 (wound inflammation, proliferation, and remodelling of the skin). All D. indusiata extracts showed good antioxidant potential, significantly anti-inflammatory activity in the decreasing of the nitric oxide (NO), interleukin-1 (IL-1), interleukin-1 (IL-6), and tumour necrosis factor-α (TNF-α) secretion from macrophage cells (p < 0.05), and the effective collagen stimulation via MMP-2 inhibition. In particular, CW extract containing high content of catechin (68.761 ± 0.010 mg/g extract) which could significantly suppress NO secretion (0.06 ± 0.02 µmol/L) better than the standard anti-inflammatory drug diclofenac (0.12 ± 0.02 µmol/L) and their MMP-2 inhibition (41.33 ± 9.44%) was comparable to L-ascorbic acid (50.65 ± 2.53%). These findings support that CW of D. indusiata could be an essential natural active ingredient for skin wound healing pharmaceutical products.