Microwave-Assisted Extraction and Phytochemical Profile of Nonea pulmonarioides and Its Antifungal, Antibacterial, and Antioxidant Activities

SUMMARY

In this study, two methods have been submitted for preparation of crude extracts, including the conventional method (Maceration) and modern method (Microwave-Assisted Extraction). Herein microwave-assisted extraction as a current approach has been chosen to extract secondary metabolites. It’s quite efficient approach as compared to the maceration process and their qualitative and quantitative analysis have been identified, as well as the antimicrobial and antioxidant activities on different solvent extracts of the Nonea pulmonarioides plant.

Folin-Ciocalteu and trichloroaluminum techniques were used to determine the total phenolic and flavonoid contents respectively. Antioxidant activity was determined by the β-carotene/linoleic acid test. About antimicrobial activity using the micro-well dilution assay method was studied for their minimal inhibition concentration (MIC). The moisture content (4.94 %) and total ash content (14.2 %) of the aerial parts Nonea pulmonarioides were determined.

Microwave-assisted extraction (MAE) represents a substantially faster extraction system (5 min) than maceration extraction (24 h). Even more, extraction yield observed in the modern method (MAE). If we compare microwave-assisted extraction (MAE) to maceration extraction (ME), there’s a lot of difference in time and solvent. In maceration for one solvent extraction of 250 g we need 2500 mL and 3 × 24 hours to reach the result however in MAE for one extraction we need 3 × 5 minute and (1300,1900 mL) for different solvent.

After extraction, solid phase extraction (SPE-C18) cartridge technique used to purify the acetone and methanolic extracts from chlorophylls.

 

A qualitative phytochemical investigation of different extracts of Nonea pulmonarioides was performed. Of the nine phytochemical tests done, anthraquinone glycoside, quinines and phlobatanins were absent in all extracts. In addition, saponins, terpenoids and steroids were present in all extracts.

Moreover, total phenolic content (TPC) and total flavonoid content (TFC) were quantified. The results of this test had a high total phenolic content (TPC) in methanol extract (113.33 ± 1.06 µg of gallic acid equivalents (GAE)/mg of dry plant), while the total flavonoid content (TFC) in acetone extract (44.26 ± 0.88 µg of quercetin equivalent (QE)/mg of the dry plant).

The quantitative GC/MS analysis of the extracts confirmed the most abundant compound was ethyl tridecanoate 45.94 % in methanol extract, while nonadecane was the predominant chemical in acetone extract 35.7 % and petroleum ether 18.34 %. Considering the results of this investigation the extract of Nonea pulmonarioides, the most important sign we got from GC-MS, which contains a high amount of polyunsaturated fatty acids (PUFA) confirms that this plant Nonea pulmonarioides is useful for antiinflammation.

Chromatography (column and MPLC) and PTLC techniques was used to isolate and purify black spot (PC1) from methanol extract. The result showed that, according to previous research, this black spot (PC1) was flavonoid.

In another part of this investigation, antioxidant activity was investigated using β-carotene/linoleic acid bleaching assay. The antioxidant activity data showed a good correlation with acetone extract (32.41 ± 0.93, I %) had a significant impact compared to other extracts.

Evaluation of the antibacterial and antifungal activity of Nonea pulmonarioides extracts against bacteria and fungi were performed. Plant extracts have interesting activity against fungi of the Candida albicans (ATCC 10231) compared to all micrograms. Additionally, it has high activity against gram positive bacteria of the Bacillus subtilis (ATCC 6633). According to the results, petroleum ether extract is a better extract for antimicrobial activities.