Kaempferol from Saffron Petals

Authors

Abstract

A flavonol, kaempferol, isolated from the fresh flower petals of C. sativus L. (Iridaceae) as the sole component. The structure of the compound was determined by chemical and spectroscopic methods.

Keywords


Kaempferol from Saffron Petals
Iranian Journal of Pharmaceutical Research (2003) 251-252
Received: June 2003
Accepted: August 2003
Original Article

 

Kaempferol from Saffron Petals

 

Farzin Hadizadeh*a,b, Naaman Khalilia, Hossein Hosseinzadeha,b, Randa Khair-Aldinea

 

aFaculty of ?Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran, ?bBu-Ali Pharmaceutical Sciences Research Center, Bu-Ali Square, Mashhad, Iran.

* Corresponding author Email: fhadizadeh@yahoo.com


 Abstract

 

A flavonol, kaempferol, isolated from the fresh flower petals of C. sativus L. (Iridaceae) as the sole component. The structure of the compound was determined by chemical and spectroscopic methods.

 Keywords: Flavonol; Kaempferol; Crocus sativus.


Introduction

 

Crocus sativus L., (Iridaceae) commonly known as saffron is native to Asia Minor and Southern Europe. It is used in folk medicine as antispasmodic, carminative, stomachic, expec?torant, aphrodisiac, cardiotonic and stimulant (1). In traditional medicine this plant is utilized as an exhilarant and curative of anxiety (2, 3). Furthermore modern pharmacological studies have demonstrated that saffron extract have antitumor effects (4), radical scavenger proper?ties (5) and hypolipaemic effects (6). In addi?tion, it has recently been found that it could be useful in neurodegenerative disorders accom?panying memory impairment (7). Also it has been recently reported that ethanol extract of Saffron petals possesses antidepressant activity (8). Phenolic compounds are likely to be the biologically active components of the petals (9). Flavanoids and anthocyanins are among phenolic compounds of this species (10). This work is a continuation of phytochemistry stud?ies on the phenolic compounds present with C. sativus and reports isolation and elucidation of a flavonoid from C. sativus petals as the sole compound, possessing pharmacological activity (11).

Experimental

 

Apparatus

1H-NMR spectra were recorded on a? Brucker Ac-100 spectrometer. UV spectra were determined in MeOH on Shimadzu UV-160A UV/VIS spectrophotometer. Thin layer chromatography was performed on silica gel plates (Merck, Germany) with the mixture HCO2H-H2O-MeOH (1:9:20).

 

Plant Material

The petals of C. sativus were collected from near the city of Torbat-Heidariye, north east of Iran in October 2000 and dried in shadow fol?lowed by grinding. The C. sativus L. was prop?erly identified by the Department of Botany Ferdowsi University, and voucher samples were preserved for reference in the herbarium of the school pharmacy, Mashhad, Iran (143-0319-1).

 

Extraction and Isolation

Powdered petals of C. sativus (100g) were extracted with MeOH containing 1% concen?trated HCl at room temperature, until complete discoloration of petals. The combined methanol extract was evaporated in vacuum at 30oC to leave a crude extract (5g). The crude extract was hydrolyzed with HCl (1.8N, 5ml for each 150mg crude extract) under nitrogen atmos?phere according to the literature (12). The re?sulting solution was extracted with amyl alco?hol (5ml x 3). The organic layer was washed with water until the pH of the aqueous phase remained constant. Organic phase was evapo?rated in vacuum to leave a residue. The struc?ture of the residue was determined by spectro?scopic methods.

 

Results and Discussion

 

Thin layer chromatography of the dried MeOH extract of petals showed only one frac?tion ( Rf = 65 ). Thin layer chromatography of acid hydrolysis product also showed only one fraction (Rf = 54). It was identified as kaempferol by 1H-NMR studies (table 1). Its NMR data was compared with that of kaempferol (13). UV spectra were taken in MeOH. Absorption maximas were 265 and 365 nm, identi?cal to that of the standard kaempferol (14). This result was in contrast to previous reports of Khorasan center of Iranian institute of science and technology which has mentioned the anthocyanidin, delphinidin, as the sole component of the C. sativus petals in the same region (11). Perhaps anthoyanid?ins of petals (e.g. pelargonidin), which with respect to their color, should be present were missing, destruc?ted or most probable oxidized to kaempferol during extraction or hydrolysis (scheme 1) process.?

 

Scheme 1

 

Isolation of flavonols, including kaempferol,? from saffron crude plant has also been previ?ously reported elsewhere in the literature (15, 16).

 

Table 1.? 1H NMR (CD3OD) spectra data of hydrolysis product and that of kaempferol reported

H

found

kaempferol

6

6.27

d

(1.90)

6.28

d

(2)

8

6.46

d

(1.94)

6.48

d

(2)

2?

8.15

d

(8.86)

8.05

d

(9)

3?

6.99

d

(8.87)

6.95

d

(9)

5?

6.99

d

(8.87)

6.95

d

(9)

6?

8.15

d

(8.86)

8.05

d

(9)

 

References

 

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