Is the first report on the inhibitio n activity of most plant

extracts against MRSA.

As phyt ochemicals o f ten play a n i mpor tant role in

plan t defe nce aga inst prey, mic roo rganis m, stress as well

as inters pecies protec tions, th ese plant comp onents have

been used as drugs for millennia. Hence, phytochemicals

scre en in g s erv es a s t he ini t ial s tep in p redic t in g t he

types of potential active compounds from plants.

The presences of flavonoids [32], triterpenoid saponins

[33] and t annins [34] in A. auriculiformis have been

re p or te d. Goo d D PP H fr ee ra di ca l s ca ven g in g ac t iv i ty o f

A. a uriculiformisis not only a ttributed to the presence

o f t a nn i n s, b ut a l so l e uc o an t ho c ya n i di n s ( l e uc o d el p h i ni -dins and l eucocyanidins) which are present abundantly

in the plant. This is because of the h ydroxylation at 4 ’

o r t ho p o s i t i o n o f l e u co an t h o c ya n i d i ns t h at c o u l d ch a n g e

DPP H radi cal to no n- radi cal DPP H-H [35] . Be sid es , tw o

acy la ted b isglyc oside s aponins, a caciaside A and B iso-lated fr om A . au r ic ul if o rm is, we r e fo un d to ex hi bi t an ti -bacterial a nd antifungal ac tivi ty. Mandal e t al. [36]

foundthatmixture ofthesetwo saponinsareableto

inhibit c onidial germinatio n of Aspergillus o chraceous

and Curvularia lunata at 300 μg/mL while the bacterici-dal co n cen tration of the mixture agai ns t Ba cillus mega-teri um , Sa lmonella ty phi murium and P. aer u gino sa was

at 700 μ g/m L or higher. A lso , three a ntifungal f lavo-noids were found in heartwood of A. a uriculi formis .

Mihara e t al. [1 8] proposed t hat t he antifunga l activity

of 3, 4’ ,7 , 8- te t ra hy dro xy fla v on e an d te ra ca ci din we re co r-rela ted to the ant iox idant act ivities , where th ese ant ifun-ga l fla v on o id s co ul d sc ave ng e t he fr ee r ad i cal s pr odu ce d

by extracellular fungal en zyme laccase, henc e inhibiting

the mycelia growth of fungus.

The e xtract of C. p u lche r ri ma has b een repo rted to

Inhibit the growth of a broad spectrum of bacteria

[19,37,38]. The extract has also shown antifungal activity

again st p lan t pa thoge ns and ye ast [37,38]. H ow ever,

none of the G ram n egat ive bacteria were i nhib ited b y

C. pulcherrima extracts i n o ur preliminary sc ree nin g.

Mukh erje e an d Ray [39] an d Ali e t a l. [19 ] reported the

presence of all f ive c lasses of phytochemicals in the

leaves while tannins, saponins a nd alka loids w er e

Chew et al . BMC Complementary and Alternative Medicine2011, 11:12

http://www.biomedcentral.com/1472-6882/11/12

Page 7 of 10

detected in the aerial p arts [15]. I n c ont rary, our f ind-ings sho wed al kalo id and s ap onin werenotdetectedin

this plant. The pre sence of gallic acid, ellagic a cid and

fl av o no i d s ( i. e. my r i ce t in , ca t ec hi n, ru ti n, an d q ue r ce ti n)

w er e fo u nd i n C. pul cherrima fl o we r s [ 40 , 4 1] . H o we v er ,

our previo u s report [4] showed t he presence of rutin

but absence of tannins a nd other flavonoids. This can

be explain ed b y t he ec ophy siol ogi cal ef fe ct a nd a biotic

gr owth fact ors that w o u ld po ssib ly be the m ajo r d eter-mining factors w hich could modify the expression of

phyt oche micals in the plant [4] . Ter penoids were found