Chemical profiling of two aromatic weeds, Cyathocline purpurea and Blumea lacera

In the present investigation chemical constituents of Cyathocline purpurea (Buch.-Ham. ex D.Don) and Blumea lacera (Burm.f.) DC. (Family-Compositae) were studied by using gas chromatography coupled with mass spectrometry (GC/MS). These two weeds are small herbs and well known for their potent medicinal properties. Total 17 and 27 compounds were identified from C. purpurea and B. lacera respectively. The major constituents in both the extracts were pentadecanoic acid, 14- methyl-, methyl ester (30.56 %), cis-phytol (21.26 %), α -cadinol (7.87 %), γ -cadinene (7.13 %), neophytadiene (3.81 %) and α -cubebene (1.82 %). GC/MS analysis revealed the presence of various bioactive compounds such as fatty acids, sesquiterpenoids, phenols, etc. in the acetone extracts of both the plants. The identified compounds have various biological activities.


INTRODUCTION
Cyathocline purpurea (Buch.-Ham. ex D.Don) Kuntze and Blumea lacera (Burm.f.) DC. are commonly found as weed and widely distributed in South Asia, which belongs to the medicinally important Compositae family [1][2][3]. These plants are small herbs with strong odor and well known for their various medicinal properties which are due to presence of various bioactive compounds [4]. C. purpurea is known for various medicinal properties such as antimicrobial, anthelmintic, anticancer and hypotensive [5][6][7]. Various phytochemicals of C. purpurea showed anti-inflammatory, antioxidant potential, anti-arthritic activity and stomach relieving properties [8][9][10]. The plant parts were used in herbal remedy to treat tuberculosis, malaria, bleeding, swelling, rheumatism and a wide range of biological activities including mutagenic, genotoxic, cytotoxic and antitumor actions [7,11]. Previously various chemical constituents were reported from this plant such as guaianolide, eudesmanolide, sesquiterpene lactones, isoivangustin and guaianolide [12]. Many sesquiterpenes lactones have shown significant antineoplastic or cytotoxic effects [6].
B. lacera is also valuable medicinal plant in many popular systems of medicine including Ayurveda, Homoeopathy and Unani. There is a heavy demand of different parts (fresh and dry both) of this weed in national and international drug markets [13]. Leaf juice is used as astringent, stimulant, anthelmintic, liver tonic, bleeding piles, diuretic, bronchitis and blood diseases [14,15]. The plant also acts as a good stomachic and antispasmodic activity [16]. It is used in folk medicine for the treatment of cough, bronchitis, dysentery and wound healing potential [17,18].
Despite the fact that, these plants can be best used for its medicinal benefits. No research is available on GC/MS profiling of weed extract of selected plants. The objective of the present study was to assess and generate the phytochemical profile of both the selected medicinally important plants by using gas chromatography techniques.

Plant Material and Extract Preparation
Plant samples (500 g) were collected from the Western Ghats of Maharashtra during flowering stages (August-September 2018). Plant samples of C. purpurea and B. lacera were collected from Bhimashankar (19°4'19.09"N, 73º32'8.5"E) and Savitribai Phule Pune University campus (18º32'53.9"N, 73º49'28.9"E) respectively. The plants were identified and authenticated from the herbarium of Department of Botany, Savitribai Phule Pune University, Pune (sweetgum.nybg.org) and assigned voucher number for C. purpurea is Bot/DNM/51/2020 and for B. lacera is Bot/DNM/52/2020. The plant materials was carefully brought to the laboratory and cleaned with distilled water. The leaves were separated from the plants and spread on a filter paper for shade drying at room temperature (27±2 o C). The dried leaves were grounded into fine powder using Wiley mill. The powder obtained was passed through 2 mm sieve. The fine powder (10 g) mixed in 100 ml of acetone (extract has been repeated thrice) and kept in shaker overnight at 25 °C at 60 rpm. The sample was filtered using Whatman filter paper no. 1 and the solvent from filtrate extract was removed on rotary vacuum evaporator (RVE) at 35-40 °C [19]. After RVE 5 g of crude extract was obtained and the obtained crude extract was greenish in colour. The extract was soluble in ethanol, methanol, chloroform and acetone. For GC/MS analysis 10 µL of crude extract was dissolved in 1 mL of acetone was used. Each experiment was performed in triplicate and mean was calculated.

Chromatographic Analysis
For preliminary screening of phytochemicals, acetone extracts of both the plants were subjected to GC/MS. GC was done by using Agilent 7890B while MS on Agilent 5977A MSD. The HP-5ms capillary column (30 m × 0.25 mm × 25 µm) was used for the sample analysis. Helium (99.999 %) was used as a carrier gas at a flow rate of 1 mL/min. The temperature for GC/ MS analysis was as follows: the injector temperature was kept at 250 ºC, the initial temperature in oven was kept at 50 ºC for 3 minute and was increased at a rate of 5 ºC per minute until 175 ºC. This temperature was maintained for 2 minute, with a total time of analysis of 30 min. MS data were recorded at 70 eV with a mass range of m/z of 45-600 amu. Single quadrupole mass spectrometer detector (150 ºC) was used in MS analysis. The information generated in GC/MS was used for quantification of compounds. For this purpose, an external standard method was used [20,21].

Identification of Compounds
The compounds were identified by the comparison of retention indices and mass spectra of most of the compounds with those of authentic compounds available in the database of National Institute Standard and Technology (NIST) and Wiley libraries. The identification was further supported by the calculation of their retention indices (RI) under identical experimental conditions using n-alkanes (C10-C40) and the calculated indices were then compared to those reported in the literature [22]. The assignments made were further confirmed by co-injection of authentic samples (Sigma-Aldrich) of the identified compounds, wherever possible [23].     and 4.54 %), ketone (9.3 and 1.15 %), fatty acyl (7.24 %) and aldehyde (0.86 %) respectively. The majority of both the plants extracts constituents were rich in fatty acids+esters and sesquiterpenoids (Table 1 and 2).
The present study revealed that the plant extracts used contain diverse phytochemicals of different chemical nature. Many of the compounds having similar chemical nature are reported to be present in other plants extracts and found to have activities against various diseases and can be used as drugs formulations.

CONCLUSION
The crude extracts of C. purpurea and B. lacera was analysed by GC/MS and the phytochemical constituents were confirmed. Both the weeds contain diverse phytochemicals such as sesquiterpenoids, fatty acids and phenols. These compounds may have some biological activities which may be exploited for bioprospecting in future. However, further research in this direction is required. These harmful weeds in agriculture field produce huge biomass which may be utilized as herbal pesticide, fungicide and herbicide. Considering the presence of different secondary metabolites they may be useful for treating disease and disorders which are to be explored.