A new biflavone glycoside from flowers of Asystasia gangetica

Abstract

The yellow parts of the flowers of Asystasia gangetica were extracted with 85% methanol under reflux. The alcoholic extract was concentrated in vacuo and the aqueous extract was fractionated with solvents of increasing polarity. The ethyl acetate fraction yielded a yellow solid, which was characterized as apigenin 7Keywords: Asystasia gangetica, Acanthaceae, biflavone glycoside.Asystasia gangetica Linn. of the Acanthaceae family is an erect, procumbent herb found in peninsular India. It is cultivated in the garden as an ornamental plant. The leaves are good sources of thiamine [1]. The juice of the plant is used as an anthelmintic. It is also given in swellings and rheumatism [2,3]. The flowers are white or yellow in color. The yellow flowers have violet or pink coloration at the center of the flower. Previous phytochemical investigations of this plant showed the presence of flavonoids [4][5][6]. With the view to locate the flavonoids of yellow flowers of this plant, yellow parts of the flowers alone were chosen, and the results are presented hereunder. They were found to contain a biflavone glycoside.The yellow flowers of Asystasia gangetica were extracted and fractionated, and the ethyl acetate extract yielded a yellow solid 1. The UV spectrum of the glycoside had O max at 340 nm (band I) and 265 nm (band II), suggesting the presence of a flavone skeleton. In the NaOMe spectrum, a bathochromic shift of 45 nm was noticed. This indicates the presence of a 4c-OH group. No bathochromic shift was noticed in the NaOAc spectrum of the glycoside, whereas a bathochromic shift of 11 nm was noticed in the case of the aglycone. This shows the absence of free OH at C-7 in the glycoside and the presence of the same in the aglycone. Spectral changes with other shift reagents could not be identified because of the superimposition of bands. The presence of free OH at C-5 was evidenced by the positive Wilson's boric acid test.In the 1 H NMR spectrum (DMSO-d 6 , TMS) of the glycoside there are two signals, one at G 12.98 and another at G 12.95, indicating the presence of two chelated hydroxyl groups. These signals are assigned to OH groups present at C-5 and C-5cc, respectively. The C-6c proton appears as a doublet at G 7.9 due to ortho coupling with H-5c. The C-5c proton appears as a doublet at G 6.9 due to ortho coupling with H-6c. The C-2c proton that is ortho to the interflavonoid linkage experiences an upfield shift and appears at G 7.62. The C-6 proton appears at G 6.44 ppm, and the C-8 proton appears as a doublet at G 6.86 due to meta coupling with H-6. The C-8cc and C-3cc protons appear as singlets at G 6.78 and G 6.74, respectively. The C-2ccc and C-6ccc protons appear at G 7.45 and G 7.42, respectively. The C-5ccc proton appears as a doublet at G 6.94 due to ortho coupling with H-6ccc (7.45) as observed in the 1 H-1 H COSY spectrum. The two doublets due to anomeric protons of the glucose units attached to the C-7 and C-7cc carbons merge at G 5.1. 13 C NMR (DMSO-d 6 , TMS) spectral data provide supporting evidence for th...

An anti-inflammatory and anti-microbial flavone glycoside from flowers of Cleome viscosa

“…Our research group has been actively involved in exploring the plant sources for isolation of bioactive compounds as well as their medicinal properties [2-7]. Cleome viscosa belongs to the Capparidaceae family.…”

“…Natural products isolated from plant sources have been demonstrated as potential candidates against several ailments [ 1 , 2 ]. Our research group has been actively involved in exploring the plant sources for isolation of bioactive compounds as well as their medicinal properties [ 2 - 7 ]. Cleome viscosa belongs to the Capparidaceae family.…”

Triterpenoids and Indole Alkaloids from the Aerial Parts of Asystasia gangetica (L.) T. Anderson

“…Địa chỉ email: hangimbc@gmail.com https://doi.org/10.25073/2588-1132/vnumps.4490 trồng tại nhiều nơi ở Hà Nội và một số tỉnh khác để làm rau ăn với tên gọi "rau ngót nhật" với công dụng giúp kích thích sữa cho phụ nữ sau sinh, giải nhiệt cơ thể, bổ huyết, nhuận tràng [2]. Các nghiên cứu trên thế giới cho thấy cây Biến hoa sông hằng (A. gangetica) đa dạng về thành phần hóa học bao gồm các hợp chất megastigman [3], flavonoid [3,4], iridoid và phenylpropanoid glycosid [5,6]. Tinh dầu từ các bộ phận trên mặt đất, hạt và rễ của cây A. gangetica cũng đã được phân tích bằng phương pháp sắc ký khí và sắc ký khí kết hợp với khối phổ [7].…”

“…Các cao chiết từ cây Biến hoa sông Hằng (A. gangetica) đã thể hiện nhiều hoạt tính sinh học đáng chú ý. Cao chiết nước lá A. gangetica làm giảm huyết áp tâm thu, tâm trương và huyết áp trung bình phụ thuộc vào liều dùng [4]. Cao chiết ethanol và cao chiết nước của toàn cây A. gangetica thể hiện tác dụng giảm đau vừa phải và tác dụng kháng viêm ở nồng độ 200 và 400 mg/kg [11].…”

Preparation of 4‐butylaniline‐bonded silica gel for the solid‐phase extraction of flavone glycosides

“…Flavone glycosides are a class of important bioactive chemical component in many medicinal plants , and all kinds of scientific research showed that they possess a series of biological and pharmacological properties including antioxidative, anti‐inflammatory, antifungal, antimicrobial antiglycation and antispasmodic, antiproliferative activities . Hence, separation and analysis of flavone glycosides are beneficial to scientific development.…”