Thitima Rukachaisirikul

Bio: Thitima Rukachaisirikul is an academic researcher from Ramkhamhaeng University. The author has contributed to research in topics: Erythrina subumbrans & Erythrina fusca. The author has an hindex of 9, co-authored 18 publications receiving 453 citations.

Chabamide, a novel piperine dimer from stems of Piper chaba.

Abstract: A novel piperine dimer, named chabamide, was isolated from stems of Piper chaba Hunter and its structure was elucidated on the basis of spectroscopic evidence. Chabamide showed antimalarial activity with an IC(50) value of 2.7 microg/ml and antituberculosis activity with the minimum inhibitory concentration (MIC) of 12.5 microg/ml.

Erythrina alkaloids and a pterocarpan from the bark of Erythrina subumbrans.

Abstract: Three new erythrina alkaloids, (+)-10,11-dioxoerythratine (1), (+)-10,11-dioxoepierythratidine (2), and (+)-10,11-dioxoerythratidinone (3), and a new pterocarpan, 1-methoxyerythrabyssin II (4), were isolated from the bark of Erythrina subumbrans, together with seven known pterocarpans, erythrabyssin II, erybraedin A, erystagallin A, erycristagallin, erythrabissin-1, eryvarin A, and hydroxycristacarpone, three flavanones, 5-hydroxysophoranone, abyssinone V, and lespedezaflavanone B, three triterpenes, sophoradiol, soyasapogenol B, and lupeol, and one isoflavanone, vogelin C. Their structures were elucidated on the basis of spectroscopic data. Some isolates were tested for antiplasmodial, antimycobacterial, and cytotoxic activities.

Biological activities of the chemical constituents of Erythrina stricta and Erythrina subumbrans.

Abstract: Phytochemical investigation of the hexane and CH2Cl2 extracts ofErythrina stricta roots andE. subumbrans stems led to the isolation of six pterocarpans, one flavanone, one isoflavone, two alkaloids, five triterpenes, six steroids and alkyl trans-ferulates. The structures of all known compounds were determined on the basis of spectroscopic evidence. Sophoradiol (15), a mixture of stigmast-4-en-3-one (19) and stigmasta-4,22-dien-3-one (20), lupeol (21), cycloeucalenol (22), a mixture of 3β-hydroxystigmast-5-en-7-one (23) and 3β-hydroxystigmast-5,22-dien-7-one (24) and melilotigenin C (25) were first isolated from the genusErythrina. The isolated compounds were evaluated for antiplasmodial activity, antimycobacterial activity and cytotoxicity. Among the tested compounds, 5-hydroxysophoranone (8) exhibited the highest antiplasmodial activity againstPlasmodium falciparum (IC50 2.5 μg/mL). Compound8, erystagallin A (5), erycristagallin (7) and erysubin F (10) showed the same level of antimycobacterial activity againstMycobacterium tuberculosis (MIC 12.5 μg/mL). For cytotoxicity, erybraedin A (2) showed the highest activity against the NCI-H187 and BC cells (IC50 2.1 and 2.9 μg/mL, respectively), whereas 10 exhibited the highest activity against the KB cells (IC50 4.5 μg/mL).

Antibacterial activity of flavonoids and their structure-activity relationship: An update review.

Abstract: Based on World Health Organization reports, resistance of bacteria to well-known antibiotics is a major global health challenge now and in the future. Different strategies have been proposed to tackle this problem including inhibition of multidrug resistance pumps and biofilm formation in bacteria and development of new antibiotics with novel mechanism of action. Flavonoids are a large class of natural compounds, have been extensively studied for their antibacterial activity, and more than 150 articles have been published on this topic since 2005. Over the past decade, some promising results were obtained with the antibacterial activity of flavonoids. In some cases, flavonoids (especially chalcones) showed up to sixfold stronger antibacterial activities than standard drugs in the market. Some synthetic derivatives of flavonoids also exhibited remarkable antibacterial activities with 20- to 80-fold more potent activity than the standard drug against multidrug-resistant Gram-negative and Gram-positive bacteria (including Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). This review summarizes the ever changing information on antibacterial activity of flavonoids since 2005, with a special focus on the structure-activity relationship and mechanisms of actions of this broad class of natural compounds.

Natural cinnamic acids, synthetic derivatives and hybrids with antimicrobial activity.

Abstract: Antimicrobial natural preparations involving cinnamon, storax and propolis have been long used topically for treating infections. Cinnamic acids and related molecules are partly responsible for the therapeutic effects observed in these preparations. Most of the cinnamic acids, their esters, amides, aldehydes and alcohols, show significant growth inhibition against one or several bacterial and fungal species. Of particular interest is the potent antitubercular activity observed for some of these cinnamic derivatives, which may be amenable as future drugs for treating tuberculosis. This review intends to summarize the literature data on the antimicrobial activity of the natural cinnamic acids and related derivatives. In addition, selected hybrids between cinnamic acids and biologically active scaffolds with antimicrobial activity were also included. A comprehensive literature search was performed collating the minimum inhibitory concentration (MIC) of each cinnamic acid or derivative against the reported microorganisms. The MIC data allows the relative comparison between series of molecules and the derivation of structure-activity relationships.