Pogostemon cablin Benth. (patchouli) is an important herb which possesses many therapeutic properties and is widely used in the fragrance industries. In traditional medicinal practices, it is used to treat colds, headaches, fever, nausea, vomiting, diarrhea, abdominal pain, insect and snake bites. In aromatherapy, patchouli oil is used to relieve depression, stress, calm nerves, control appetite and to improve sexual interest. Till now more than 140 compounds, including terpenoids, phytosterols, flavonoids, organic acids, lignins, alkaloids, glycosides, alcohols, aldehydes have been isolated and identified from patchouli. The main phytochemical compounds are patchouli alcohol, α-patchoulene, β-patchoulene, α-bulnesene, seychellene, norpatchoulenol, pogostone, eugenol and pogostol. Modern studies have revealed several biological activities such as antioxidant, analgesic, anti-inflammatory, antiplatelet, antithrombotic, aphrodisiac, antidepressant, antimutagenic, antiemetic, fibrinolytic and cytotoxic activities. However, some of the traditional uses need to be verified and may require standardizing and authenticating the bioactivity of purified compounds through scientific methods. The aim of the present review is to provide comprehensive knowledge on the phytochemistry and pharmacological activities of essential oil and different plant extracts of patchouli based on the available scientific literature. This information will provide a potential guide in exploring the use of main active compounds of patchouli in various medical fields.

A Comprehensive Review on the Phytochemical Constituents and Pharmacological Activities of Pogostemon cablin Benth.: An Aromatic Medicinal Plant of Industrial Importance

Plants and microbes commonly make terpenes and terpenoids in small amounts and as complex mixtures, and their chemical synthesis is often costly and inefficient. Hence, there are many efforts to create robust and efficient biological production platforms for this interesting class of molecules. In this study, our effort was directed towards building a yeast production platform using an unbiased genetic selection approach. Yeast strain BY4741 was subjected to EMS mutagenesis, followed by selection for growth in the presence of nystatin, squalestatin, and exogenous cholesterol. This unbiased screen selected for mutant yeast lines having a dispensable mevalonate pathway and containing uncharacterized SUE (sterol uptake enhancement) mutations supporting aerobic uptake of exogenous sterol. These mutants were next screened for high level accumulation of farnesol (FOH), an indicator for high level accumulation of the key intermediate FPP, farnesyl diphosphate. To further improve the FPP pool in these mutants, insertional mutations into the ERG9 gene (coding for squalene synthase) were introduced into those lines capable of accumulating ≥50 mg farnesol/L. This generated another series of lines that accumulated farnesol levels over 70 mg/L in small-scale shake cultures. To evaluate the utility of these lines as a general production platform for specific terpenes, select SUE/erg9 lines were transformed with a vector harboring the Hyoscyamus muticus premnaspirodiene synthase (HPS) gene encoding for a sesquiterpene synthase. The new yeast line ZX178-08 accumulated the highest level of premnaspirodiene, up to 116 mg/L, with FOH levels of 23.6 mg/L. In comparison, the parental line BY4741 accumulated 10 times less premnaspirodiene, 10.94 mg/L, with no farnesol detectable. Co-expression of the HPS gene with an amino-terminal truncated, catalytic form of the hamster HMGR gene, tHMGR, increased premnaspirodiene accumulation to 170.23 ± 30.44 mg/L, almost a 50% increase. Further utility of this yeast line was demonstrated for triterpene production. When engineered for the production of a non-native triterpene, Zx178-08 accumulated upwards of 60 mg/L of botryococcene. To engineer more native triterpene accumulation, additional insertion mutants into the ERG1 gene (coding for squalene epoxidase) were evaluated. Insertion of a simple selection marker followed by over-expression of a heterologous squalene synthase gene resulted in greater than 85 mg/L of squalene. However, when the ERG1 insertional mutant included chromosomal insertion of a truncated, heterologous HMGR gene, squalene production was more than tripled to 270 mg/L. These results are discussed in comparison to other recently developed terpene production platforms. Biotechnol. Bioeng. 2015;112: 1854–1864. © 2015 Wiley Periodicals, Inc.

Building terpene production platforms in yeast

Pogostemon cablin (Blanco) Benth. (Patchouli) is an important aromatic and medicinal plant and widely used in traditional Chinese medicine as well as in the perfume industry. Patchoulol is the primary bioactive component in P. cablin, its biosynthesis has attracted widespread interests. Previous studies have surveyed the putative genes involved in patchoulol biosynthesis using next-generation sequencing method; however, technical limitations generated by short-read sequencing restrict the yield of full-length genes. Additionally, little is known about the expression pattern of genes especially patchoulol biosynthesis related genes in response to methyl jasmonate (MeJA). Our understanding of patchoulol biosynthetic pathway still remained largely incomplete to date. In this study, we analyzed the morphological character and volatile chemical compounds of P. cablin cv. ‘Zhanxiang’, and 39 volatile chemical components were detected in the patchouli leaf using GC-MS, most of which were sesquiterpenes. Furthermore, high-quality RNA isolated from leaves and stems of P. cablin were used to generate the first full-length transcriptome of P. cablin using PacBio isoform sequencing (Iso-Seq). In total, 9.7 Gb clean data and 82,335 full-length UniTransModels were captured. 102 transcripts were annotated as 16 encoding enzymes involved in patchouli alcohol biosynthesis. Accorded with the uptrend of patchoulol content, the vast majority of genes related to the patchoulol biosynthesis were up-regulated after MeJA treatment, indicating that MeJA led to an increasing synthesis of patchoulol through activating the expression level of genes involved in biosynthesis pathway of patchoulol. Moreover, expression pattern analysis also revealed that transcription factors participated in JA regulation of patchoulol biosynthesis were differentially expressed. The current study comprehensively reported the morphological specificity, volatile chemical compositions and transcriptome characterization of the Chinese-cultivated P. cablin cv. ‘Zhanxiang’, these results contribute to our better understanding of the physiological and molecular features of patchouli, especially the molecular mechanism of biosynthesis of patchoulol. Our full-length transcriptome data also provides a valuable genetic resource for further studies in patchouli.

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Full-length transcriptome sequencing and methyl jasmonate-induced expression profile analysis of genes related to patchoulol biosynthesis and regulation in Pogostemon cablin

Patchouli (Pogostemon cablin) is shade loving plant and the shade dried leaves are used for essential oil extraction which is used in high-quality perfumery. The present study is aimed to find the ...

Standardization of Different Drying Methods of Fresh Patchouli (Pogostemon cablin) Leaves for High Essential Oil Yield and Quality

Transcriptional responses for biosynthesis of flavor volatiles in methyl jasmonate-treated Chrysanthemum indicum var. aromaticum leaves

Patchouli ( Pogostemon cablin Benth.) is a plant from Lamiaceae family , well known for its medicinal and aromatic properties. Patchouli is grown for its essential oil. Patchouli essential oil is mainly obtained by steam distillation of the shade dried leaves. It is widely appreciated for its characteristic pleasant and long lasting woody, earthy, camphoraceous odour. It is especially notable as the essential oil extracted is internationally important and valuable, principally for the aromatherapy, perfumery, cosmetics, incense stick production and food flavouring industries. This review attempt ed to give an overview of the relationship between aromatherapy and essential oils, importance of patchouli, harvesting pattern of patchouli, basics behind drying and steam distillation of patchouli crop, as well as trends existing in the various markets for essential oil application and its importance to mankind. Keywords: p atchouli, a romatherapy, d rying, s team distillation, e ssential oil, a pplications

An introduction to patchouli (Pogostemon cablin Benth. ) - A medicinal and aromatic plant: It's importance to mankind

Biodiesel generated from a variety of non-edible feedstocks has gained widespread acceptance as a limited diesel fuel alternative in compression ignition engines. For the reliable implementation of biodiesel in commercial sectors, its effect on engine combustion, emission, and performance needs to be examined experimentally. In this study, 10% (N10) and 20 % (N20) Neem oil methyl ester (NME) blends were tested in a direct injection 4-stroke single-cylinder diesel engine incorporated with 5% and 10% exhaust gas recirculation (EGR). At maximum load conditions, Brake thermal efficiency (BTE) was found highest for N20 by 7.2%, and also Brake specific energy consumption (BSEC) was reduced by 11.4% for N20 as compared to diesel. Meanwhile, the incorporation of EGR deteriorates the performance parameters for the N20 blend. The results of emission analysis showed that oxides of nitrogen (NOx) increased with the addition of biodiesel whereas the addition of EGR diminished the NOx value for both biodiesel blends at all loading conditions. Unburnt hydrocarbon (UHC), Carbon monoxide (CO), and smoke emissions decreased by 40.6%, 31.2%, and 29.6% for the N20 blend respectively at full load when compared to diesel. Interestingly, when EGR was provided, CO, UHC, and smoke density values are increased for both N10 and N20 blends at all loading conditions, however lower than diesel operation.

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Assessment of Diesel Engine Performance, Combustion and Emission Characteristics with Supplementation of Neem Oil Methyl Ester Along With EGR

Synergetic effect OF CI engine characteristics when fuelled with neem oil methyl ester enriched with a oxy-hydrogen gas

Severe and adverse energy crises in future, day by day ever elevating cost of fuels, dangerous emissions emitted with conventional fuels made internal combustion engine scientists to discover and look at the likelihood of usage of alternate, clean and less or zero emissions fluids and vaporous fuels for IC engines, especially compression ignition diesel engines (DE) since existing DE are under stringent pollutions regulation that too for smoke and NOx in their tail pipe fumes. The main target of this work is to examine the emission, combustion and performance attributes of a diesel engine running with a wide range of loads with a constant speed of 1500rpm with a 30% steedy energy share of CNG and varying EGR of 5%,10% and 15% using diesel as pilot fuel. BSEC of dual fuel mode engine is discovered superior to neat diesel engine mode at higher load. It is discovered that there is an uncommon decrease in NOX, CO2, and smoke density, increment in UHC, CO in the fumes of dual fuel engine at all loads. Comparative results are given for dual fuel mode with variable measures of EGR at various loads conditions and detailed the impact of the application of EGR on combustion, performance and emission processes.

Combined Effect of CNG and EGR on the Performance, Emission and Combustion Characteristics of Diesel Engine in Dual Fuel mode

In the current state of affairs, the global concern is about greenhouse gas emission into the environment and ambient air pollution driven by massive consumption of fossil fuels by the various automobile and power generating sectors. One of the most excellent solutions to control the above concern is to develop and employ carbon-neutral fuels in internal combustion engines. Water electrolyzed hydroxyl gas (HHO gas) is the imperative and promising alternate fuel to pure fossil fuels. In this study, the performance, combustion, and emission characteristics of a 3.7 kW single cylinder four stroke CI engine enriched with HHO gas supplied to the intake manifold with the constant speed of 1500 RPM using diesel as a pilot fuel are studied. In this investigation, HHO gas was generated through the electrolysis of water and utilized to exterminate the handling and safety-related issues originated by compressed hydrogen. The examinations are repeated with HHO blend of 5, 10 and 15% with various Exhaust Gas Recirculation (EGR) proportions to study the impact of HHO gas and EGR on dual fuel mode of diesel engine. The dual-fuelled (diesel + HHO gas) engine’s performance, combustion, and emission parameters are presented and compared in both analytical and graphical approaches. The results obtained at full load conditions are exhibited and compared with neat diesel operation. The brake thermal efficiency is higher by 9.6% for 15% HHO gas without EGR. NOx emission is almost similar for 10% HHO gas with 10 and 15% EGR. Smoke and greenhouse gas emissions are lower by 33.3% and 13.2% respectively for 15% HHO gas without EGR. Reduction in CO and HC emissions are noticed in dual-fuel operation.

V. Palanimuthu

Papers

An introduction to patchouli (Pogostemon cablin Benth. ) - A medicinal and aromatic plant: It's importance to mankind

Assessment of Diesel Engine Performance, Combustion and Emission Characteristics with Supplementation of Neem Oil Methyl Ester Along With EGR

Synergetic effect OF CI engine characteristics when fuelled with neem oil methyl ester enriched with a oxy-hydrogen gas

Combined Effect of CNG and EGR on the Performance, Emission and Combustion Characteristics of Diesel Engine in Dual Fuel mode

Effect of Supplementing Water Electrolyzed Hydroxyl Gas and Exhaust Gas Recirculation in the Combustion Process of a Compression Ignition Engine