IR Spectrum of Poncirin, Contoh sebuah spektrum inframerah dari sebuah komponen organik

IR spectrum of Poncirin

Gambar di atas, sebuah spektrum inframerah (IR) dari sebuah organic compound, poncirin, yang umunya dapat dijumpai pada genus Ponciri, kerabat dekat dengan keluarga jeruk. Oleh sebab itu komponen ini diberi nama Poncirin. Seperti halnya cinnamaldehide dan cinnamic acid yang merupakan senyawa utama dari tanaman cinnamon (kayu manis), beberapa species dari genus Cinnamomun. Di bawah ini struktur kimia dari poncirin.

Chemical structure of Poncirin

Poncirin termasuk kelompok Flavanone (Flavonoids), dicirikan tanpa adanya ikatan rangkap pada posisi C-2 dan C-3. Poncirin merupakan glycoside (rutinoside: rhamnose attached at 2 position of glucose) dari isosakuranetin. Dengan kata lain, isosakuranetin adalah aglycone dari poncirin. dicirikan dengan adanya gugus metoksil pada posisi 4 di ring B (C-4'). Berikut ini diberikan assignments beberapa peak (jumlah gelombang per cm) dari IR spectrum di atas terhadap beberapa gugus fungsi (functional group) dari poncirin.

• 3422 (3500 - 3200) = gugus hidroksil (alkohol OH, strecth), broad. Banyak terlihat gugus OH.
• 2922 (3000 - 2900) = aromatic C-H pada aglycone moiety.
• 2840 (2860 - 2820) = gugus metoksil pada aglycone (O-CH3).
• 1643 (1680 - 1620) = keton pada ring C of aglycone (C=O).
• 1579 (1700 - 1500) = aromatic double bond (C=C).
• 1449 (1460 - 1410) = methylene (CH2).
• 1373 (1380 - 1350) = methyl (CH3).
• 1179 (1260 - 1000) = C-O.
• 1050 (1100 - 1000) = glycosidic C-O (glycosidic linkage).

Demikian sedikit penjelasan mengenai identifikasi spektrum inframerah pada contoh senyawa poncirin, semoga bermanfaat untuk kita semua.

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Analysis of Quinic Acid Derivatives on Seven Cultivars of the Lettuce (Lactuca sativa L.) and Peroxynitrite Scavenging Effect

Abstract

The compositional analysis and the peroxynitrite (ONOO-) scavenging assay were undertaken to demonstrate beneficial dietary effect of lettuce (Lactuca sativa L., Compositae). Quinic acid derivatives of the seven cultivars were qualitatively and quantitatively analyzed by HPLC to lead to the finding of 3,4-di-O-caffeoyquinic acid and 3-O-p-coumaroylquinic acid and their contents ranged over 2.72-4.47 mg/g and 8.97-23.26 mg/g, respectively. A cultivar Hacheong had the highest quantity of quinic acid derivatives. The peroxynitrite scavenging effect of the five cultivars (Jangsu, Gosina 27, Gopung, Yeolpungjeogchima,
and Mipungjeogchugmyeon) were ranged over 7.45-8.26μg/ml as IC50s while those of Hacheong and Mihong had less effect (IC50 >10 μg/ml).

Keywords: Lactuca sativa, Compositae, peroxynitrite, quinic acid, HPLC

Korean Journal of Pharmacognosy 40(4): 376-381 (2009).

Available at http://naturalproduct.skku.edu/erp/erpmenus/professor_thesis/uploadfiles/KJP%202009-1.pdf

Further information: agungnug19@gmail.com

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Quantitative Analsysis of Flavanone Glycosides and Peroxynitrite Scavenging Effect of the Five Oriental Medicinal Drugs (Aurantii nobilis Pericarpium, Citrii unshiu Pericarpium, Citrii unshiu Semen, Aurantii Fructus, Poncirii Fructus)

Abstract

Overproduction of peroxynitrite (ONOO-) causes a variety of disease such as atherosclerosis, hypercholesterolemia, diabetes mellitus or obesity. Peroxynitrite scavenging activities and HPLC analysis on the five Oriental medicinal drugs belonging to the genus Citrus, Aurantium or Poncirus (Rutaceae family) and HPLC analysis were taken to evaluate flavanone glycosides with peroxynitrite scavenging activity. The IC50s of the five crude drugs were shown as follows: Aurantii nobilis Pericarpium (Jinpi, 18.3 μg/ml), Citrii unshiu Pericarpium (Chungpi, 7.50μg/ml), Citrii unshiu Semen (Gyulhaek, >50.0μg/ml), Aurantii Fructus (Jigak, 18.3μg/ml), and Poncirii Fructus (Jisil, >50.0μg/ml) where Korean crude drug’s names are noted in the parenthesis. Peroxynitrite scavenging effect of flavanones or their glycosides usually contained in Citrus species were observed as follows: hesperetin (1.89 μg/ml), naringenin (7.77 μg/ml), hesperidin (8.44 μg/ml), poncirin (>50.0 μg/ml) and ponciretin(>50.0 μg/ml). The activities of naringin and poncirin with α-L-rhamnopyranosyl(1→2)-β-D-glucopyranosyl moiety were weak. HPLC analytical data revealed that Jinpi (the peels of mature fruits of Citrus unshiu) and Chungpi (the peels of immature fruits of C. unshiu) had high quantities of hesperidin as the value of 142.1±0.21 and 104.51±1.10 mg/g dried weight, respectively. Poncirin was clearly detected in only Jisil and naringenin and naringin were not observed on the HPLC chromatogram of the five crude drugs.

Keywords: Citrus, peroxynitrite, flavanone glycosides, hesperidin, HPLC

Korean Journal of Pharmacognosy 40(4): 370-375 (2009).

Available online at http://210.101.116.28/W_files/kiss2/05004572_pv.pdf

Further information: agungnug19@gmail.com

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HPLC Analysis of Caffeoylquinic Acids in the Extract of Cacalia firma and Peroxynitrite Scavenging Effect

Abstract

Six caffeoylquinic acids of Cacalia firma (Komarov) Nakai (Compositae) leaves were identified using standard compounds by HPLC. Each content of those compounds in dried weight was determined as follows: 3,4-di-O-caffeoylquinic acid (1.44±0.04 mg/g of dried weight), 3,5-di-O-caffeoyl-muce-quinic acid (2.47±0.12 mg/g), 3,5-di-O-caffeoylquinic acid (3.74±0.24 mg/g), 5-caffeoylquinic acid (chlorogenic acid, 5.20±0.09 mg/g), 3-caffeoylquinic acid (1.35±0.01 mg/g) and 3-Op-coumaroylquinic acid (3.84±0.25 mg/g). The total content of six caffeoylquinic acids in the plant material was calculated as 18.05±0.69 mg/g while the percentage of the six compounds in the MeOH extract was calculated as 30.85±1.18%. The IC50 value of the MeOH extract scavenging peroxynitrite (ONOO-) was shown as 3.22±0.57 μg/ml.

Keywords: Cacalia firma, Compositae, caffeoylquinic acid, peroxynitrite, HPLC

Korean Journal of Pharmacognosy 40(4): 365-369 (2009).

Available online at http://naturalproduct.skku.edu/erp/erpmenus/professor_thesis/uploadfiles/2009-2.pdf

Further information: agungnug19@gmail.com

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Qualitative and Quantitative Determination of the Caffeoylquinic Acids on the Korean Mountainous Vegetables Used for Chwinamul and Their Peroxynitrite-Scavenging Effect

Abstract 

Mountainous vegetables called chwinamul are used in Korea to promote health. Chwinamul was obtained from several plants belonging to the Compositae - e.g., Kalimeris yomena, Aster scaber, Solidago virga var. gigantea, Solidago viragaurea var. asiatica, Saussurea grandifolia, Ainsliaea acerifolia - were used for our experiments. Analytical methods for simultaneous determination of the caffeoylquinic acids (3,4-di-O-caffeoylquinic acid, 3,5-di-O-dicaffeoyl-epi-quinic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, 5-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, 3-O-p-coumaroyl-caffeoylquinic acids) were established for chwinamul. The kinds of constituents were identified from HPLC chromatograms and it was possible to calculate the percentage (w/w) of seven of these compounds in the dried plants and in the extracts. The proportion of caffeoylquinic acids in the extracts ranged from 20.25 to 38.35%. Since it is known that peroxynitrite (ONOO(-))-scavenging is beneficial for amelioration of obesity, diabetes mellitus, atherosclerosis and even Alzheimer's disease, assays for peroxynitrite-scavenging activity were performed on the seven chwinamul plants. Of the tested extracts, the MeOH extract of A. acerifolia had the most potent effect (IC(50) 1.49 +/- 0.68 microg/mL). These results suggest that chwinamul vegetables can be used for treatment or prevention of peroxynitrite-related diseases.

Archives of Pharmacal Research 32(10): 1361-1367 (2009). DOI 10.1007/s12272-009-2003-6.

Available online at http://link.springer.com/article/10.1007%2Fs12272-009-2003-6

Further information: agungnug19@gmail.com

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Two New Flavonol Glycosides from Lamium amplexicaule L. and Their in vitro Free Radical Scavenging and Tyrosinase Inhibitory Activities

Abstract
Two new flavonol glycosides, kaempferol 3-O-[β-D-glucopyranosyl-(1→4)][α-L-rhamnopyranosyl-(1→6)]-β-D-glucopyranoside and quercetin 3-O-[β-D-glucopyranosyl-(1→4)][α-L-rhamnopyranosyl-(
1→6)]-β-D-glucopyranoside, together with three known flavonoids were isolated using column chromatography from the aerial parts of Lamium amplexicaule (Labiatae). In addition,
the five isolates were evaluated for their in vitro free radical scavenging (EC50 values, 14.1–63.9 μg/mL) and tyrosinase inhibitory activities (IC50 values, 110.4–193.5 μg/mL).

keywords:
Lamium amplexicaule, Labiatae, flavonol glycosides, free radical scavenging, tyrosinase inhibitors

Planta Medica 75(4): 364-366 (2009). DOI: 10.1055/s-0028-1112216.

Available online at https://www.thieme-connect.com/DOI/DOI?10.1055/s-0028-1112216

For further information: agungnug19@gmail.com

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Memahami UV spektrofotometri

Sebagai asisten profesor di lab, setiap semester saya ditugasi untuk menghandel mata kuliah praktikum, yaitu Natural Product Analysis dan juga Instrumental Analysis. Di sini saya ingin mendokumentasikan beberapa praktikum yang saya anggap dapat memberi tambahan informasi untuk pembaca sekalian. Selain itu setiaap saat saya juga dapat mereview kembali dengan membuka blog ini.

Baik, untuk kali ini akan dibahas mengenai UV spektrofotometri.

Ultraviolet merupakan radiasi elektromagnet yang memiliki panjang gelombang antara 10 nm hingga 800 nm (lebih pendek daripada radiasi cahaya tampak, tapi lebih panjang daripada sinar X). UV spektrofotometer adalah instrumen analisis yang biasa digunakan untuk menganalisa senyawa kimia dengan memanfaatkan ultraviolet.

Seperti pernah dibahas pada artikel sebelumnya, tentang spektroskopi inframerah (IR), pada dasarnya sejumlah besar senyawa organik menyerap/mengabsorbsi sejumlah energi dari radiasi ultraviolet. Prinsip inilah yang diaplikasikan pada instrumen UV spektrofotometer untuk menganalisa suatu senyawa organik. Perbedaan struktur dan gugus fungsi pada setiap senyawa organik menyebabkan perbedaan daya absorpsinya terhadap radiasi ultraviolet, sehingga spektrum yang ditampilkan sebagai hasil analisis dari instrumen akan berbeda-beda untuk setiap senyawa kimia.

Contoh sebuah UV spektrum

Kemudian, bagaimana daya absorbsi suatu senyawa bisa diukur? UV spektrofotometer mengukur daya serap senyawa dengan mengkalkulasi perbedaan energi yang dimiliki suatu panjang gelombang sebelum dan setelah melewati (diabsorbsi) senyawa tersebut yang ditempatkan pada suatu bejana (cell atau cuvette) dengan standar lebar 10 mm. Perbedaan energi inilah yang diterjamahkan oleh alat dalam sebuah spektrum yang berupa sebuah peak (band).

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