SECONDARY METABOLITES FROM CRYPTOCARYA PLANTS (LAURACEAE) INDONESIAN WITH BIOACTIVITY

• Main Author: Siallagan, Johnson
• Format: Dissertations
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/52117
• Institution: Institut Teknologi Bandung

Cryptocarya, locally known as “medang” or “huru”, is one of important genera of Lauraceae family. The plants are found in the temperate and subtropical region, which its distribution includes in Asia, Australia and Melanesia. Cryptocarya species are economically important for building materials, furnitures, and pulp. In addition, several species of Cryptocarya have also been used as traditional medicines to cure various diseases like skin diseases, muscle aches, joint pain, headache, nausea, infections due to fungi and bacteria. From previous phytochemical studies, Cryptocarya produces several types of secondary metabolites, including 2-pyrones, flavonoids, alkaloids, lignans, stilbenoids, terpenoids, and steroids. Of these metabolites, 2-pyrones, flavonoids and alkaloids are typical for this genus. Structural features of 2-pyrones are usually substituted at C-6 with a side chain of alkyl, aryl and aryl-alkyl, and bicyclo pyrones. In the flavonoids, dihydrochalcones, chalcones and flavanones are more common and contains structural features in the B ring of the flavanone are unoxygenated. However, several flavonoids isolated from Cryptocarya condense with other flavonoids compounds or with other groups such as 2-pyrones to produce flavonoid derivatives with a high level of complexity. Alkaloid derivatives so far known for this genus are benzylisoquinolines, aporphines and oxoaporphines skeleton. Based on this background, the research was aimed to investigate phytochemical diversity of four species of Cryptocarya, namely C. everettii Merr, C. lucida Blume, C. massoy (Oken) Kosterm and C. mentek Blume ex Nees, and cytotoxic evaluation of the isolated compounds against murine leukemia cells P-388. Based on the variation of IC50 data, this study also examined the structure-activity relationship between structures and cytotoxicity of the metabolites found in the four species. Samples of the stem bark of C. everettii were obtained from Central Sulawesi, the bark of C. lucida were collected from Bukit Bengkirai, Balikpapan, East Kalimantan, the bark of C. massoy collected from Sabiyap Village, District Kemtuk Gresi, Jayapura regency, Papua, and the bark of C. mentek collected from Dolok Simardaging, Sibolga, Central Tapanuli, North Sumatra. The isolation of secondary metabolites involved a number laboratory works, including extraction by using maceration techniques, fractionation, and purification using various chromatographic techniques. The molecular structure of the isolated compounds were determined on the basis of spectroscopic data including UV, IR, NMR-1D (1H and 13C), NMR-2D (COSY, HMQC, HMBC, and NOESY), as well as high resolution mass spectroscopy (FAB-MS and HRESI-MS). Cytotoxicity assay was carried out against murine leukemia P-388 cells lines using MTT [3-(4,5- dimethyltiazo-2-yl-)-2,5-diphenyltetrazoliumbromide] assay. This research has succeeded in isolating 20 secondary metabolites, including three new compounds menteklakton A (1) and menteklakton B (2) (2-pyrones derivatives oxygenated in the 2-pyrone ring) and menteklakton C (3). Seventeen other compounds are known compounds that includes two 2-pyrones derivatives, namely massoialactone (4) and goniothalamin (5); three chalcone derivatives, namely infectocaryone (6), kurzichalcolactone A (7) and kurzichalcolactone B (8); four flavanone derivatives, namely pinocembrin flavanones (9), pinostrobin (10), and an unseparable mixture of cryptocaryanone A (11) and B (12); two tyramine derivatives, namely N-trans-feruloyltyramine (13) and N-trans-feruloyl- 3-methoxytyramine (14); two arylpropanoid derivatives, coniferaldehyde (15) and sinapaldehyde (16); one lignan derivative, syringaresinol (17), one alkaloid derivative palidine (18), and two sesquiterpenes, namely 10?-hydroxicadinane-4- en-3-on (19) and 4(15)-eudesmane-11-ol (20). The investigation of new compounds menteklakton A (1), menteklakton B (2) and menteklakton C (3) is a very important chemical data to the phytochemistry of Cryptocarya, and Lauraceae in general. Menteklakton A (1) and menteklakton B (2) are 2-pyrones derivatives that structurally differents to the 2-pyrones compounds that have previously been reported from Cryptocarya. The differences lies in the presence of additional oxygenated functionality at C-5 of the 2-pyrone ring and an epoxide in the side chain. Menteklakton C (3), on the other hand, is a 2-pyrone derivative containing a side chain with high oxygenation. These additional structural diversity indicates that this genus is able to develop its secondary metabolites by making a variation of oxygenation in the structure of the secondary metabolites. Furthermore, the presence of flavonoids of chalcone and flavanone types, namely infectocaryone (6) and an inseparable mixture of cryptocaryanones A (11) and B (12), containing a partially reduced A ring, which biogenetically they should be originated from the condensation of a cinnamoyl unit with four units of acetyl, are not common in the plant’s flavonoids. This gives an additional evidence that Cryptocarya is the most advance genus in the family Lauraceae. Moreover, fourteen other compounds also increase the diversity of secondary metabolites in Cryptocarya. Cytotoxic evaluation of the isolated compounds against murine leukemia P-388 cells showed that compounds 1, 2, 5, 6, 11 and 12 could inhibit the growth of P- 388 cell with very active cytotoxicities (IC50 < 10 ?M), while compounds 3, 4, and 7 could be classified as having only active cytotoxicities (IC50 10 – 20 ?M), while eleven other compounds were inactive (IC50 > 20 ?M). Structure-activity relationship on these cytotoxic data revealed that 2-pyrones skeleton appeared to be important in providing high cytotoxicity, and the presence of oxygenated functionality at C-5 as a hydroxyl group also played a role in enhancing cytotoxicity. However, the 2-pyrones derivatives with an alkyl side chain showed less cytotoxic activity, indicating that the side chain with an aromatic substituen also gives a significant contribution to the cytotoxicity. In the flavonoid derivatives, the presence of A ring modification gave cytotoxic properties of very active compare to the normal flavonoid structures. In conclusion, this study has successfully isolated three new compounds, namely menteklakton A (1), menteklakton B (2) (2-pyrones derivatives oxygenated in the 2-pyrone ring), and menteklakton C (3) (a 2-pyrone with highly oxygenated in the side chain moiety). The finding of these compounds has given a new knowledge on the phytochemistry and biogenesis of this genus. Furthermore, the presence of other seventeen compounds, with a high number of structural variation, give a more firm position that the genus can produce more varried groups of secondary metabolites compared to the other genera in the family Lauraceae. Furthermore, based on the cytotoxic properties against P-388 cells, the 2-pyrones in general are more active than other type of compounds, while chalcone and flavanone containing a partially reduced A ring are highly active in inhibiting the cells.