Evaluation of the Topical Anti-Inflammatory Activity of Ginger Dry Extracts from Solutions and Plasters

Abstract

In this study the skin permeation and the topical anti-inflammatory properties of ginger extracts were investigated. A commercial ginger dry extract (DE) and a gingerols-enriched dry extract (EDE) were evaluated for their in vivo topical anti-inflammatory activity by inhibition of Croton oil-induced ear oedema in mice. Furthermore, the feasibility of an anti-inflammatory plaster containing DE or EDE was evaluated. Since the in vivo activity was evaluated in mice, the ex vivo skin permeation study was performed by using mouse skin or human epidermis. The DE from the acetonic solution exerted a dose-dependent topical anti-inflammatory activity (ID (50) = 142 microg/cm (2)), not far from that of the potent reference substance indomethacin (ID (50) = 93 microg/cm (2)). Similarly, the EDE induced a dose-dependent oedema reduction though its potency (ID (50) = 181 microg/cm (2)) was slightly lower than that of DE. Increase of the 6-gingerol concentration in the extract did not improve the anti-inflammatory activity. The medicated plasters, containing 1 mg/cm (2) of the commercial DE or EDE, had good technological characteristics and exerted a significant antiphlogistic effect, too. By using the plaster containing EDE, the 6-gingerol amount that permeated through human epidermis was 6.9 microg/cm (2) while the amount that passed through mouse skin was 22.1 microg/cm (2). Nevertheless, the amounts of 6-gingerol permeated through human epidermis and mouse skin in the early period (8h) were comparable (p > 0.3). This preliminary result suggests that the anti-inflammatory effect observed in mice could also be exerted in humans.

Gingerol Derivatives from the Rhizomes of Zingiber Officinale

“…The HMBC experiment also showed the long-range couplings H-1/C-1 , H-1/C-2 , H-1/C-6 , and H-2/C-1 , which indicated that the alkyl chain is linked to the aromatic ring. Therefore, the structure of 1 was again deduced as a sulfonated gingerol derivative, named [8]-gingesulfonic acid (Fig. 1).…”

“…Comparison of the spectroscopic and physical data with those published allowed us to establish the structures of nine known gingerol derivatives, [6] As mentioned above, three sulfonated derivatives of gingerol were isolated from Zingiber officinale, and their structures were established as [8]-gingesulfonic acid (1), [10]-gingesulfonic acid (2), and [6]-gingesulfonic acid (3). However, the stereochemistry at C-5 of 1 -3 is still under investigation.…”

“…In addition, the signals at δ H =3.37/δ C = 57.17 due to H-5/C-5 resembled those of [6]-gingesulfonic acid [18]. Hence, 1 was characterized as a 5-dehydroxy 5-sulfonated derivative of [8]gingerol, and named [8]-gingesulfonic acid.…”

“…In this study, we report the isolation of two new sulfonated gingerol derivatives, [8]-gingesulfonic acid (1) and [10]-gingesulfonic acid (2), along with nine known gingerol derivatives, [6]-gingesulfonic acid (3) [11], 1-dehydro- [6]-gingerdione (4) [1], 1-dehydro- [8]-gingerdione (5) [1,12], 1-dehydro- [10]gingerdione (6) [12], [6]-gingerdione (7) [13], [10]gingerdione (8) [13], [6]-gingerol (9) [14,15], methyl [6]-gingerdiol (10) [16], and 6-hydroxyl- [6]-shogaol (11) [17] (Fig. 1).…”

“…Gingerols, the so-called "pungent principles", are the constituents responsible for the taste of ginger [1]. Phytochemical and pharmacological reports have shown that the major bioactive constituents of ginger, the gingerols, possess the following activities: anti-platelet aggregation [2,3], anticancer [4 -6], anti-oxidation and anti-inflammation [7,8], inhibition of COX-2 expression [9], antifungal [10] and others. Therefore the isolation and purification of the gingerols and their derivatives from ginger are of great interest.…”