Determination of Patchoulic Alcohol in Herba Pogostemonis by GC-MS-MS

Essential Oils: Chemistry and Pharmacological Activities-Part II

The importance of essential oils and their components in the industrial sector is attributed to their chemical characteristics and their application in the development of products in the areas of cosmetology, food, and pharmaceuticals. However, the pharmacological properties of this class of natural products have been extensively investigated and indicate their applicability for obtaining new drugs. Therefore, this review discusses the use of these oils as starting materials to synthesize more complex molecules and products with greater commercial value and clinic potential. Furthermore, the antiulcer, cardiovascular, and antidiabetic mechanisms of action are discussed. The main mechanistic aspects of the chemopreventive properties of oils against cancer are also presented. The data highlight essential oils and their derivatives as a strategic chemical group in the search for effective therapeutic agents against various diseases.

Biotransformation of Patchouli Alcohol by Cladosporium cladosporioides and the Anti-Influenza Virus Activities of Biotransformation Products

The biotransformation of patchouli alcohol by Cladosporium cladosporioides afforded 31 products, including 21 new ones (1-3, 5, 6, 8-14, and 17-25). Their structures were determined by extensive spectroscopic data analysis (1H and 13C NMR, HSQC, HMBC, 1H-1H COSY, ROESY, and HRESIMS), and the absolute configuration of compounds 1, 2, 8, 9, and 17 was determined by single-crystal X-ray diffraction using Cu Kα radiation. Structurally, compounds 21-24 were patchoulol-type norsesquiterpenoids without Me-12. Among them, a Δ3(4) double bond existed in compounds 21 and 22; a three-membered ring was formed between C-4, C-5, and C-6 in compound 23; an epoxy moiety appeared between C-3 and C-4 in compound 24. Furthermore, the biotransformation products 9, 10, 12, and 25 showed potent anti-influenza virus activity with EC50 values of 2.11, 7.94, 20.87, and 3.45 μM, respectively.

Polysaccharides From Pogostemon cablin (Blanco) Benth.: Characterization and Antioxidant Activities

Two polysaccharide fractions from Pogostemon cablin (Blanco) Benth. (P. cablin) (designated as PCB-1 and PCB2-1) were isolated by water extraction and purified by Sepharose chromatography. The chemical properties of the polysaccharides were characterised, and their antioxidant activities were evaluated. The sugar content of the crude polysaccharide (PCB), PCB-1, and PCB2-1 was 58.74, 90.23 and 88.61%, respectively. The molecular weights of PCB-1 and PCB2-1 were determined to be 97.8 and 12.8 kDa, respectively. Monosaccharide composition analysis showed that all the three polysaccharides consisted of mannose, rhamnose, galacturonic acid, galactose, glucose, and arabinose, but with varying molar ratios. The polysaccharides exhibited significantly high antioxidant activities in vitro based on the scavenging activity against hydroxyl radicals, metal ion-chelating and ferric-reducing abilities. In vivo experiments in an oxidatively damaged mice model showed that PCB-1 increased the levels of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase, and inhibited malondialdehyde formation in the serum and liver. These findings suggest that PCB-1 has significant potential as an antioxidant in functional foods.

Characterization of a Cytosolic Acyl-Activating Enzyme Catalyzing the Formation of 4-Methylvaleryl-CoA for Pogostone Biosynthesis in Pogostemon Cablin

Pogostone, a compound with various pharmaceutical activities, is a major constituent of the essential oil preparation called Pogostemonis Herba, which is obtained from the plant Pogostemon cablin. The biosynthesis of pogostone has not been elucidated, but 4-methylvaleryl-CoA (4MVCoA) is a likely precursor. We analyzed the distribution of pogostone in P. cablin using gas chromatography-mass spectrometry (GC-MS) and found that pogostone accumulates at high levels in the main stems and leaves of young plants. A search for the acyl-activating enzyme (AAE) that catalyzes the formation of 4MVCoA from 4-methylvaleric acid was launched, using an RNAseq-based approach to identify 31 unigenes encoding putative AAEs including the PcAAE2, the transcript profile of which shows a strong positive correlation with the distribution pattern of pogostone. The protein encoded by PcAAE2 was biochemically characterized in vitro and shown to catalyze the formation of 4MVCoA from 4-methylvaleric acid. Phylogenetic analysis showed that PcAAE2 is closely related to other AAE proteins in P. cablin and other species that are localized to the peroxisomes. However, PcAAE2 lacks a peroxisome targeting sequence 1 (PTS1) and is localized in the cytosol.

Protective effect of pogostone on murine norovirus infected-RAW264.7 macrophages through inhibition of NF-κB/NLRP3-dependent pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Pogostemon cablin, the dry overground parts of Pogostemon cablin (Blanco) Benth, has been widely used in the treatment of gastrointestinal dysfunction, such as nausea, diarrhea, headaches and fever. Pogostone (PO) is a major component of Pogostemon cablin which has a variety of pharmacological properties, including antiinflammatory, and immunosuppressive activities, and antioxidant. However, the effect of PO on norovirus gastroenteritis and the underlying molecular mechanism remain unclear.

AIM OF THE STUDY

The purpose of our study is to investigate the effects of PO against MNV infection using RAW264.7 cells and to elucidate its active mechanisms.

MATERIALS AND METHODS

The cell viability was assessed using Cell Counting Kit-8 (CCK-8) assay and Fluorescein diacetate (FDA) staining. The activation of nuclear factor kappa B (NF-κB) signaling and NOD-like receptor 3 (NLRP3) inflammasome was evaluated by assessing the level of phospho-NF-κB p65, interleukin (IL)-6, TNF-α, NLRP3, cleaved caspase-1, IL-18, IL-1β using Western blot and quantitative real-time PCR (qPCR), respectively. The number of infected cells were determined by immunofluorescence microscopic assay.

RESULTS

PO did not possess a cytotoxic effect toward RAW264.7 cells. The cytotoxic damage caused by MNV infection in RAW264.7 cells decreased significantly in the presence of PO. Cell viability assays showed that pyroptosis is the major mechanism of death in MNV-infected RAW264.7 cells. PO could decreased the expression levels of p-p65, IL-6, TNF-α, NLRP3, cleaved caspase-1, IL-1β, and IL-18.

CONCLUSIONS

These results demonstrate that PO decreases MNV-induced RAW264.7 macrophages death and MNV replication through repressing NF-κB/NLRP3-dependent pyroptosis. Therefore PO may be considered as a potential therapeutic agent for preventing and treating norovirus gastroenteritis.

Protective role of β-patchoulene from Pogostemon cablin against indomethacin-induced gastric ulcer in rats: Involvement of anti-inflammation and angiogenesis

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) are most widely used as effective anti-inflammatory agents. However, their clinical application brings about inevasible gastrointestinal side effects. Pogostemon cablin is a traditional herbal medicine used for the treatment of gastrointestinal diseases in China. One of its representative components, the tricyclic triterpenoid β-patchoulone (β-PAE) has demonstrated great anti-inflammatory activity and gastroprotective effect against ethanol-induced gastric injury, but its protective effect against gastric ulcer induced by indomethacin is still unknown.

PURPOSE

To assess the protective effect of β-PAE against ulcer produced by indomethacin and reveal the underlying pharmacological mechanism.

STUDY DESIGN

We used an indomethacin-induced gastric ulcer model of rats in vivo.

METHODS

Gastroprotective activity of β-PAE (10, 20, 40 mg/kg, i.g.) was estimated via indomethacin-induced gastric ulcer model in rats. Histopathological and histochemical assessment of ulcerated tissues were performed. Protein and mRNA expression were determined by Elisa, Western blotting and qRT-PCR.

RESULTS

β-PAE could inhibit ulcer formation. Histopathological and histochemical assessment macroscopically demonstrated that β-PAE alleviates indomethacin-induced gastric ulceration in dose-dependent manner. After administration of β-PAE, elevated tumor necrosis factor -α level was significantly decreased and the phosphorylation of JNK and IκB was markedly inhibited. β-PAE suppressed the levels of E-selectin, P-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule and monocyte chemoattractant protein 1, as well as myeloperoxidase. Meanwhile, β-PAE increased cyclooxygenase enzyme activities (COX-1 and COX-2) to enhance the production of prostaglandin E₂. Proangiogenic protein, vascular endothelial growth factor and its receptor fms-like tyrosine kinase-1 mRNA expression were promoted while anti-angiogenic protein, endostatin-1 and its receptor ETAR mRNA expression were decreased.

CONCLUSION

β-PAE may provide gastroprotection in indomethacin-induced gastric ulcer in rats by reducing inflammatory response and improving angiogenesis.

Molecular Role of EGFR-MAPK Pathway in Patchouli Alcohol-Induced Apoptosis and Cell Cycle Arrest on A549 Cells In Vitro and In Vivo

Nowadays, chemotherapy is still the main effective treatment for cancer. Herb prescriptions containing Pogostemon cablin Benth (also known as "Guang-Huo-Xiang") have been widely used in Chinese medicine today. In our research, we found that patchouli alcohol, a compound isolated from the oil of Pogostemon cablin Benth, exerted antitumor ability against human lung cancer A549 cells ability both in vitro and in vivo. MTT assay was used to assess cell viability. Hoechst 33342 staining and TUNEL cover glass staining provided the visual evidence of apoptosis. Caspase activity measurement showed that patchouli alcohol activated caspase 9 and caspase 3 of mitochondria-mediated apoptosis. Consistently, patchouli alcohol inhibited the xenograft tumor in vivo. Further investigation of the underlying molecular mechanism showed that MAPK and EGFR pathway might contribute to the antitumor effect of patchouli alcohol. Our study proved that patchouli alcohol might be able to serve as a novel antitumor compound in the clinical treatment of lung cancer.

In Vitro and In Vivo Antibacterial Activity of Patchouli Alcohol from Pogostemon cablin

OBJECTIVE

To investigate the antibacterial activity of patchouli alcohol (PA) against 127 bacteria strains, including the common bacteria and drug-resistant bacteria strains both in the in vitro and in vivo tests.

METHODS

For the in vitro trial, the antibacterial property of PA against 107 Gram-positive and 20 Gram-negative bacteria strains was screened by agar double dilution method. For the in vivo trial, specific pathogen free Kunming strain of both male and female white mice, were used to test the protective ability of PA after being injected with the median lethal dose of the tested strains.

RESULTS

PA possessed antibacterial activity against all the tested 127 strains. In the in vitro test, PA could inhibit both Gram-negative bacteria (25-768μg/mL) and Gram-positive bacteria (1.5-200μg/mL). Particularly, PA was active against some drug-resistant bacteria like methicillin-resistant Staphylococcus aureus (MRSA). PA also exhibited in vivo anti-MRSA activity in mice via intraperitoneal injection. PA could protect mice entirely infected with MRSA at 100 and 200 mg/kg, while 80% mice injected with MRSA could be protected at a low dose of 50μg/mL.

CONCLUSION

PA might be a potential antibacterial drug from natural sources and might be worthy to explore its mechanism and application in further study.

Design, synthesis, and biological evaluation of crenatoside analogues as novel influenza neuraminidase inhibitors

Natural products, especially derived from TCMH, have been found to exert antiviral effects against influenza virus. Crenatoside, a phenylethanoid glycoside from Pogostemon cablin Benth, which has been shown as a novel effective NA inhibitor previously, is considered as the leading compound for our further SARs studies. This work presented design, synthesis of novel crenatoside analogues from readily available d-Glucose and l-rhamnose in a convergent manner. Furthermore, their biological activities and SARs were also investigated. Especially, compound 2 h showed impressive IC50 = 27.77 μg/mL against NAs, which is 3 folds more potent than the leading compound crenatoside (IC50 = 89.81 μg/mL). These results would promise their therapeutic potential for influenza disease.

The gastroprotective effect of pogostone from Pogostemonis Herba against indomethacin-induced gastric ulcer in rats

Pogostemonis Herba, known as "Guang-Huo-Xiang" in Chinese, has been widely used in the treatment of gastrointestinal dysfunction. Pogostone is one of the major constituents of Pogostemonis Herba. The aim was to scientifically evaluate the possible gastroprotective effect and the underlying mechanisms of pogostone against indomethacin-induced gastric ulcer in rats. Rats were orally treated with vehicle, lansoprazole (30 mg/kg) or pogostone (10, 20 and 40 mg/kg) and subsequently exposed to acute gastric lesions induced by indomethacin. Gross evaluation, histological observation, gastric mucosal superoxide dismutase activity, glutathione content, catalase activity, malonaldehyde level and prostaglandin E2 production were performed. Immunohistochemistry and reverse transcription polymerase chain reaction for cyclooxygenase-1 and cyclooxygenase-2, as well as terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, immunohistochemistry for heat-shock protein 70, B-cell lymphoma-2 and Bax were conducted. Results indicated that rats pretreated with pogostone showed remarkable protection from the gastric mucosa damage compared to vehicle-treated rats based on the ulcer index and inhibition percentage. Histologically, oral administration of pogostone resulted in observable improvement of gastric injury, characterized by reduction of necrotic lesion, flattening of gastric mucosa and alleviation of submucosal edema with hemorrhage. Pogostone pretreatment significantly raised the depressed activities of superoxide dismutase, glutathione and catalase, while reduced the elevated malonaldehyde level compared with indomethacin-induced group. Pogostone-pretreated group induced a significant increase in gastric mucosal prostaglandin E2 level and obvious up-regulation of protein levels and mRNA expressions of cyclooxygenase-1 and cyclooxygenase-2. Furthermore, antiapoptotic effect of pogostone was verified by terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay, and the apoptotic process triggered by pogostone involved the up-expression of heat-shock protein70 and B-cell lymphoma-2 protein, and suppression of Bax protein expressions in the ulcerated tissues. It is speculated that the gastroprotective effect of pogostone against indomethacin-induced gastric ulceration might be associated with its stimulation of cyclooxygenase-mediated prostaglandin E2, antioxidant and antiapoptotic effect.

Protective effects of pogostone from Pogostemonis Herba against ethanol-induced gastric ulcer in rats

We examined the protective effect of pogostone (PO), a chemical constituent isolated from Pogostemonis Herba, on the ethanol-induced gastric ulcer in rats. Administration of PO at doses of 10, 20 and 40 mg/kg body weight prior to ethanol ingestion effectively protected the stomach from ulceration. The gastric lesions were significantly ameliorated by all doses of PO as compared to the vehicle group. Pre-treatment with PO prevented the oxidative damage and the decrease of prostaglandin E2 (PGE2) content. In addition, PO pretreatment markedly increased the mucosa levels of glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT), and decreased gastric malonaldehyde (MDA), relative to the vehicle group. In the mechanistic study, significant elevation of non-protein-sulfhydryl (NP-SH) was observed in the gastric mucosa pretreated by PO. Analysis of serum cytokines indicated that PO pretreatment obviously elevated the decrease of interleukin-10 (IL-10) level, while markedly mitigated the increment of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) secretions in ethanol-induced rats. Taken together, these results strongly indicate that PO could exert a gastro-protective effect against gastric ulceration, and the underlying mechanism might be associated with the stimulation of PGE2, improvement of antioxidant and anti-inflammatory status, as well as preservation of NP-SH.

Effects of topical application of patchouli alcohol on the UV-induced skin photoaging in mice

Ultraviolet (UV) irradiation, known to generate reactive oxygen species (ROS) excessively and elicit inflammatory response, is a potent inducer for skin photoaging. Overproduction of ROS in conjunction with the resulting inflammation stimulate the over-expression of matrix metalloproteinases (MMPs), which in turn causes degradation of extracellular matrix, leading finally to coarse wrinkling, dryness, and laxity of the skin. In this study, patchouli alcohol (PA, C15H26O), an active chemical ingredient reputed for free radical scavenging and anti-inflammatory properties, was investigated for its anti-photoaging action using a mouse model whose dorsal skin was depilated. The dorsal skin areas of six-week-old mice were smeared with PA solution or vehicle, followed by UV irradiation for nine consecutive weeks. Protective effects of PA were evaluated macroscopically and histologically, as well as by assaying the antioxidant enzymes (SOD, GSH-Px) activities, the contents of inflammatory factors (IL-10, IL-6, TNF-α), and the levels of MMP-1 and MMP-3. Our findings amply demonstrated that PA significantly accelerated the recovery of the UV-induced skin lesions, evidently through anti-oxidant and anti-inflammatory action, as well as down-regulation of the MMP-1 and MMP-3 expression.

Anti-inflammatory effect of patchouli alcohol isolated from Pogostemonis Herba in LPS-stimulated RAW264.7 macrophages

Pogostemonis Herba has long been used in traditional Chinese medicine for the treatment of inflammation-related disorders. Patchouli alcohol (PA) isolated from Pogostemonis Herba is a tricyclic sesquiterpene that is known to exert a variety of pharmacological activities. The present study aimed to investigate the anti-inflammatory effect of PA on lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Pre-treatment with PA at concentrations of 10, 20 or 40 μM dose-dependently decreased the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, nitric oxide (NO) and prostaglandin E(2) in LPS-stimulated RAW264.7 cells. In addition, PA treatment also reversed the increased mRNA expression of TNF-α, IL-1β, IL-6, inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 caused by LPS in RAW264.7 cells. These results indicate that PA is an important anti-inflammatory constituent of Pogostemonis Herba and that its anti-inflammatory effect may be mediated, at least in part, by down-regulation of the mRNA expression of a panel of inflammatory mediators, such as TNF-α, IL-1β, IL-6, iNOS and COX-2.

Analgesic and Anti-Inflammatory Activities of the Methanol Extract from Pogostemon cablin

Pogostemon cablin (PC) is a herbal medicine traditionally applied to treat not only common cold, nausea and diarrhea but also headache and fever. The aim of this study was to investigate the analgesic and anti-inflammatory properties of standardized PC methanol extract (PCMeOH) in vivo. Investigations were performed in mice with two analgesic models. One was acetic acid-induced writhing response and the other formalin-induced paw licking. The anti-inflammatory effect was tested by λ-carrageenan (Carr)-induced mice paw edema. These analgesic experimental results indicated that PCMeOH (1.0 g/kg) decreased the acetic acid-induced writhing responses and PCMeOH (0.5 and 1.0 g/kg) decreased the licking time in the second phase of the formalin test. Moreover, Carr-induced paw edema inflammation was significantly reduced in a dose-dependent manner when PCMeOH (0.5 and 1.0 g/kg) was administered 3 and 4 h after the Carr injection. Mechanistic studies showed that PCMeOH decreased the levels of malondialdehyde in the edema paw by increasing the activities of anti-oxidant enzymes, such as superoxide dismutase, glutathione peroxidase and glutathione reductase, in the liver and decreasing the cyclooxygenase 2 and tumor necrosis factor-α activities in the edema paw. This study has demonstrated the analgesic and anti-inflammatory effects of PCMeOH, thus verifying its popular use in traditional medicine.

Analysis of the volatile compounds in Senecio scandens Buch-Ham by gas chromatography-tandem mass spectrometry based on diversified scan technologies

Static headspace gas chromatography-tandem mass spectrometry was used to identify volatile compounds from Senecio scandens Buch-Ham. The elemental composition of compounds was confirmed by exploiting the tandem mass spectra of isotopic peaks from the precursor ion. Some isomers were well distinguished by the diversified scan technologies of tandem mass spectrometry (MS/MS). The MS/MS included a product ion scan, a precursor ion scan and a neutral loss scan. The results showed that 46 volatile compounds were completely identified, and the great of majority compounds were α-pinene (11.93%), n-caproaldehyde (9.02%) and dehydrosabinene (6.22%). This qualitative method is convenient and accurate and can be considered as a complementary identification method for the qualitative analysis of volatile compounds in complex samples.

Natural sesquiterpenoids

This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature from January to December 2005 is reviewed,and 386 references are cited.