Exp 10 510.docx

TITLE: Qualitative Analysis of Vietnamese Coriander Herb by Gas Chromatography-Mass Spectrometry (GC-MS) INTRODUCTION: Plants in general have long been a source of biologically active compounds; extracts of herbs have been used widely as alternatives to pharmaceuticals. Many compounds such as antimicrobial, antiseptic, sedative and diuretic compounds can be isolated from a single herb. Today, a large portion of prescription drugs is still derived from plants. Plant distillates contain compounds with an essence with oily consistency which is called essential oil. Menthol has been used externally as a mild local anesthetic and antiseptic and it has been used internally as gastric sedative. Vietnamese coriander (Persicaria odorata) is a member of the knotweed family and is also known as Vietnamese mint or Rau Ram. It’s a tender perennial and thrives from late spring to early autumn. It will eventually succumb to frost, but you can bring the plants indoors and place them on a sunny windowsill for winter harvesting. OBJECTIVE: 

To perform an extraction of Vietnamese Coriander herb by liquid-liquid extraction.



To analyze and identify constituents in the essential oil of Vietnamese Coriander herb by using GC-MS.

REAGENTS AND SOLUTIONS: 

Analytical grade methanol



Analytical grade dichloromethane



Anhydrous magnesium sulfate

SAMPLE: 

Dried Vietnamese Coriander herb leaves (100 g)

APPARATUS: 

Round bottom flask



West condenser



250 mL separatory funnel



13 mm diameter syringe filter (0.25 𝜇m pore size)

INSTRUMENT: 

Gas chromatography (Agilent Technologies 6890N) equipped with HP 5971A mass selective detector (MSD) and 30 m x 0.25 𝜇m HP5-MS capillary column.

PROCEDURE: a. Sample Preparation

1. About 3-4 g of Vietnamese Coriander herb leaves were chopped and 25 mL of methanol was added in a round bottom flask. 2. A condenser packed with glass beads was placed in a vertical position above and connect directly to the round-bottom flask. 3. The mixture was percolated for 30 minutes at a gentle boil with refluxing. 4. The cooled solution was decanted from the round-bottom flask and then, extracted with 5 mL dichloromethane in a 250 mL separatory funnel. 5. The organic layer was removed and dried with 1 g anhydrous magnesium sulfate. 6. The mixture was filtered to remove any particulate matter.

b. Instrument Set-up (may vary depending on instrument): Injection port

: split(20:1)

Injection port temperature

: 280 oC

Oven temperature

: Initial temperature 70 oC for 4 min. Then ramp the temperature at 10 oC min-1 up to 140 oC and 20 oC min-1 up to 280oC.

Column flow rate

: 40 mL min-1

Detector temperature

: 290 oC

c. Separation of essential oils in Vietnamese Coriander herb. 2 𝜇L of each sample was extracted. If necessary, temperature programming may be altered to optimize the separation.

d. Identification of essential oil constituents in sample extract. The major compounds in the extract were identified by comparing their mass spectra with the library in the GC-MS database.

RESULTS:

Vietnamese coriander (daun kesum): No.

Retention time

Area(%)

Library/ID

Quality

1.

13.432

4.47

Decanal

99

2.

16.541

18.72

Dodecanal

98

3.

17.714

12.57

Alpha humulene

95

4.

17.627

11.40

Beta caryophyllene

97

DISCUSSION:

In this experiment of Vietnamese coriander analysis, 4 constituents of oil essential were found. The first peak gave the retention time of 13.432 min and 4.47%. With the 99% quality, the constituent was determined as Decanal (C10H20O). Decanal was a saturated fatty aldehyde formally arising from reduction of the carboxy group of capric acid (decanoic acid). It has a role as an antifungal agent, a fragrance and a plant metabolite. It is a saturated fatty aldehyde and a nalkanal (Bochra, 2015).

Decanal

The second essential oil found was Dodecanal (C12H24O) with the quality 98%, retention time of 16.541 min and area 18.72%. Dodecanal known as Lauric aldehyde was found in citrus. Lauric aldehyde occurs in peel oil from Citrus species and kumquat. Also present in ginger, coriander, chervil and scallop. Lauric aldehyde was a flavouring agent. Dodecanal was a longchain fatty aldehyde that was dodecane in which two hydrogens attached to a terminal carbon were replaced by an oxo group (Bochra, 2015). It has a role as a plant metabolite. It was a 2,3saturated fatty aldehyde and a long-chain fatty aldehyde. It derives from a hydride of a dodecane.

Dodecanal

Alpha humulene (C15H24) or alpha-caryophyllene has the retention time of 17.714 min with the area 12.57% and quality of 95%. Humulene was an isomer of β-caryophyllene, and the two were often found together as a mixture in many aromatic plants. α-Humulene has been found in many aromatic plants on all continents, often together with its isomer β-caryophyllene. αHumulene was contained in the essential oils of aromatic plants such as Salvia officinalis (common sage, culinary sage), up to 29.9% of the essential oils of Mentha spicata, 10% of the leaf oil of Litsea mushaensis, 4% of the leaf extract of Cordia verbenacea and 25% transCaryophyllene which one of the chemical compounds that contribute to the taste of the spice Persicaria odorata or Vietnamese coriander and the characteristic aroma of Cannabis (‘Gardening Savvy’,2018).

α- humulene Beta-Caryophyllene (C15H24), also known as caryophyllene or (−)-β-caryophyllene has retention time of 17.627 min with the area 11.4% and 97% of quality, was a natural bicyclic sesquiterpene that was a constituent of many essential oils including that of Syzygium aromaticum (cloves), Cannabis sativa, rosemary, and coriander. It was usually found as a mixture with isocaryophyllene (the cis double bond isomer) and α-humulene (obsolete name: αcaryophyllene), a ring-opened isomer. beta-Caryophyllene is notable for having both a cyclobutane ring and a trans-double bond in a nine-membered ring, both rarities in nature (Properzi, 2012). Beta-Caryophyllene was a sweet and dry tasting compound that can be found in a number of food items such as allspice, fig, pot marjoram, and roman camomile, which makes beta-caryophyllene a potential biomarker for the consumption of these food products.

β-caryophyllene

These 4 constituents in essential oils found as the highest quality in the Vietnamese coriander. Chemical and nutrient content in Vietnamese coriander were decanal, dodecanol, decanol, alpha humulene and beta caryophyllene.

In this experiment, the error might happened such as during preparation of Vietnamese coriander, the herbs did not dry thoroughly and some moisture might retained inside leaves. Dry herb was neeeded to increase the surface area in order for better extraction. Dry weighed herbs always give less error than fresh plants because fresh herbs can change according to climate or weather before it extracted in the laboratory. Other than that, dry process of herb should be conducted in control space because to prevent any particulate matter or moisture from mix with herbs.

CONCLUSION:

In conclusion, the Vietnamese coriander leaves were extracted by liquid-liquid extraction. The Vietnamese coriander was succesfully extracted and the greenish organic layer of extraction was observed. The constituents of essential oil in the Vietnamese coriander was analyzed from the chromatogram of Mass-spectrometry detector. The Vietnamese coriander showed the presence of four essential oils which were decanal, dodecanal, alpha-humulene and beta-caryophyllene with 99%, 98%, 95% and 97% of quality respectively.

REFERENCES:

Bochra, L., Karima, K., Mahmoud, M. and Taoufik B.(2015). Coriander (Coriandrum sativum L.)

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its

bioactive

constituents.

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9–26.

Retrieved

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http://dx.doi.org/10.1016/j.fitote.2015.03.012. Properzi A, Angelini P, Bertuzzi G, Venanzoni R. Some biological activities of essential oils. Med Aromatic Plants 2012;2(5):1–4. PubChem(2018). Humulene: USA: pubchem.ncbi.nlm.nih.gov. Access on 28 October 2018 from https://pubchem.ncbi.nlm.nih.gov/compound/Humulene#section=Top Sasongko, Pramono & Laohankunjit, N & Kerdchoechuen, Orapin. (2011). Antibacterial Activity of the Essential Oil from Persicaria odorata Leaves. Agricultural Science Journal. 42. 105-108. ‘Savvy Gardening’(2018). Get to know Vietnamese coriander: USA: savvygardening.com. Access on 28 October 2018 from https://savvygardening.com/vietnamese-coriander/ Schnaubelt, K. (2002). Biology of Essential Oils. San Rafael, CA: Terra Linda Scent.