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ABSTRACT. Sesquiterpenoids are a class of terpenoid compounds with a remarkable diversity of structures and biological activities. Sesquiterpenoids are primarily found in higher plants, such as the Meliaceae family's Aglaia genus. Aglaia cucullata is a species of Aglaia that is still rarely explored and can potentially contain sesquiterpenoid compounds with cytotoxic activity. Hence, the research intended to isolate sesquiterpenoids from the n-hexane extract of A. cucullata stem bark and evaluate their cytotoxic effect against A549 lung cancer cells. Compounds 1 and 2 were isolated and purified from n-hexane extracts utilizing various chromatographic techniques. The structure of compounds 1 and 2 was determined by analyzing various spectroscopic methods (IR, MS, and NMR) and comparing them to previously reported spectral data. Compound 1 was identified as an isodaucane-type sesquiterpenoid, 10-hydroxy-6,10-epoxy-7(14)-isodaucane, and was first reported in Meliaceae family. Compound 2 was confirmed as an eudesmane-type sesquiterpenoid, eudesm-4(15)-ene-1β,6α-dihydroxy, and was first reported in Aglaia cucullata. Cytotoxic activity of 1 and 2 were investigated in vitro against A549 lung cancer cells using the PrestoBlue assay and resulted in inactive and low cytotoxicity with IC50 values of 292.77 and 90.55 μM, respectively. Key words: Aglaia cucullata, , A549 cell lines, cytotoxic activity, Meliaceae, sesquiterpenoids.

Four triterpenoids, known as dammarane-type, dammaradienone (1), 20(S),25-epoxy-5α-dammar-20-en-3-one (2), 20(S)-5α-dammar-24-en-3α,20-diol-3-acetate (3) and 3α-acetyl-20S,24S-epoxy-25-hydroxydammarane (4), were isolated from Aglaia cucullata peel fruit. The structures of isolated compounds were identified based on their HR-TOFMS data and extensive NMR spectroscopic analysis, as well as compared with literature data. Compounds 1-4 were assessed for cytotoxic effects against HeLa cervical and B16-F10 melanoma skin cancer cells. All compounds showed moderate to weak activity against B16-F10 cancer cells, while compound 2 exhibited the strongest activity against HeLa cancer cells with IC50 of 7.10 µg/mL indicating that the existence of an epoxy moiety at the side chain increases the cytotoxicity to HeLa cells.

With about 120 species, Aglaia is one of the largest genera of the plant family Meliaceae (the mahogany plants). Various Aglaia species have been investigated since the 1960s for their phytochemical constituents and biological properties. This research objective was to find secondary metabolites that have activity as anti-breast cancer compounds from endemic Indonesian Aglaia, such as Aglaia angustifolia Miq. Two cholestan type steroids, stigmast-5en-3α-acetat (1), as a new steroid with α-sterochemistry of acetyl moiety at C-3 and 23a-homostigmast-5en-3β-ol (2), with unusual side chain were isolated for the first time from the stem bark of Aglaia angustifolia Miq or known as segara tree in Kalimantan. The chemical structures of two steroids were identified with spectroscopic data, including IR, NMR (1H, 13C, DEPT 135°, HMQC, HMBC, NOESY, 1H-1H COSY) and HRTOF-MS, as well as by comparing with previously reported spectral data. These two steroids were isolated for the first time from this genus. Steroids 1 and 2 were evaluated for cytotoxic activity against MCF-7 breast cancer cells and showed weak activity with IC50 values of 829.0 and 903.0 µg/mL, respectively.

Bacicyclin is a cyclic hexapeptide with antibacterial activity against Enterococcus faecalis and Staphylococcus aureus with minimum inhibition concentration (MIC) values of 8 and 12 µM, respectively. Studies on a reversed sequence of bacicyclin were conducted to investigate how the reversed peptide sequence affects its biological properties. A reversed-bacicylin, cyclo-(Gly-Leu-Val-Ile-Ala-Phe), was successfully synthesized by constructing the linear precursor on 2-chlorotrityl chloride resin using a Fmoc-based strategy. The HATU/HOAt reagent was applied in all peptidic bond formations, and the desired linear hexapeptide (82% yield) was cleaved off the resin using a mixture of trifluoroacetic acid:dichloromethane (2:8). The linear peptide was cyclized using 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium-3-oxidehexa-fluorophosphate (HATU) as a coupling agent and diisopropylethylamine (DIPEA) as the base in a very dilute solution (0.001 M) in dichloromethane, then purified by octadecyl silica gel (ODS) column chromatography to obtain the reversed-bacicyclin (43.7% yield). The purity of the cyclic product was analyzed using analytical RP-HPLC (tR = 20.01 min), and characterized by HR-TOF-MS, 1H-NMR, and 13C-NMR. The biological activity of the reversed-bacicyclin is much lower compared to bacicyclin, indicating that the amino acid sequence of the cyclopeptide dictates the antibacterial activity. This finding gives additional information on the relationship between peptide sequence and biological properties.

Epimerisation is basically a chemical conversion that includes the transformation of an epimer into another epimer or its chiral partner. Epimerisation of amino acid is a side reaction that sometimes happens during peptide synthesis. It became the most avoided reaction because the process affects the overall conformation of the molecule, eventually even altering the bioactivity of the peptide. Epimerised products have a high similarity of physical characteristics, thus making it difficult for them to be purified. In regards to amino acids, epimerisation is very important in keeping the chirality of the assembled amino acids unchanged during the peptide synthesis and obtaining the desirable product without any problematic purification. In this review, we report several factors that induce epimerisation during peptide synthesis, including how to characterise and affect the bioactivities. To avoid undesirable epimerisation, we also describe several methods of suppressing the process.

Peptide compounds play a significant role in medicinal chemistry as they can inhibit the activity of species that cause malaria. This literature review summarizes the isolation of antimalarial peptides, the synthesis method with the detailed structure and sequences of each peptide, and discusses the biological activity of the isolated and synthesized compounds. The synthetic routes and reactions for cyclic and linear antimalarial peptides are systematically highlighted in this review including preparing building blocks, protection and deprotection, coupling and cyclization reactions until the target compound is obtained. Based on the literature data and the results, this review’s aim is to provide information to discover and synthesize more antimalarial peptide for future research.

Limonoid is derivatives of triterpenoid compound that have a wide variety of structures due to various ring-opening, rearrangements, and high-degree of oxidation. Limonoid is known as compounds that have wide-range of biological activities, including anticancer activity. This research was aimed to determine the chemical structure and cytotoxic activity of limonoid in the n-hexane extract of Chisocheton lasiocarpus fruit. Dried powder of C. lasiocarpus fruit was extracted using methanol followed by fractionated using n-hexane, ethyl acetate, and n-butanol. Five azadirone-type limonoids, 6α-(acetoxy)-14β,15β-epoxyazadirone (1), dysobinin (2), 7α-acetylneotricilenone (3), 6α-O-acetyl-7-deacetylnimocinol (4), and 7α-hyroxyneotricilenone (5), were isolated from the n-hexane extract of Chisocheton lasiocarpus fruit. The chemical structure of all compounds was identified by spectroscopic analysis, including 1D, 2D-NMR, IR, UV and HR-TOF MS as well as by comparison with previous reported spectra data. Compounds 1-5 were investigated from this plant for first time. The cytotoxic activity of the isolated compounds against MCF-7 breast cancer line were examined and the results showed that 7α-hyroxyneotricilenone (5) showed the moderate activity with IC50 values of 53 μM

Cyclopurpuracin is a cyclooctapeptide isolated from the methanol extract of Annona purpurea seeds with a sequence of cyclo-Gly-Phe-Ile-Gly-Ser-Pro-Val-Pro. In our previous study, the cyclisation of linear cyclopurpuracin was problematic; however, the reversed version was successfully cyclised even though the NMR spectra revealed the presence of a mixture of conformers. Herein, we report the successful synthesis of cyclopurpuracin using a combination of solid- and solution-phase synthetic methods. Initially, two precursors of cyclopurpuracin were prepared, precursor linear A (NH2-Gly-Phe-Ile-Gly-Ser(t-Bu)-Pro-Val-Pro-OH) and precursor linear B (NH-Pro-Gly-Phe-Ile-Gly-Ser(t-Bu)-Pro-Val-OH, and various coupling reagents and solvents were trialled to achieve successful synthesis. The final product was obtained when precursors A and B were cyclised using the PyBOP/NaCl method, resulting in a cyclic product with overall yields of 3.2% and 3.6%, respectively. The synthetic products were characterised by HR-ToF-MS, 1H-NMR, and 13C-NMR, showing similar NMR profiles to the isolated product from nature and no conformer mixture. The antimicrobial activity of cyclopurpuracin was also evaluated for the first time against S. aureus, E. coli, and C. albicans, showing weak activity with MIC values of 1000 µg/mL for both synthetic products, whereas the reversed cyclopurpuracin was more effective with an MIC of 500 µg/mL.

Three aromadendrane-type sesquiterpenoids, spathulenol (1), 4β,10α-dihydroxyaromadendrane (2), and 4α,10α-dihydroxyaromadendrane (3) were isolated from the stem bark of Aglaia harmsiana (Meliaceae). Compound 3 was isolated for the first time from Aglaia genus. The chemical structures of isolated compounds were elucidated by various spectroscopic methods, including one and two-dimensional NMR, as well as mass spectroscopy analysis. These sesquiterpenoids 1-3 were evaluated for their cytotoxic activity against MCF-7 breast cancer cell lines. The IC50 value of compound 1-3 were 31.65 ± 0.1, 8.41 ± 0.04 and 2.80 ± 0.02 µM, respectively. Among the aromadendrane-type sesquiterpenoids, compounds 2 and 3, which do not have a double bond, showed higher activity than compound 1. Whereas, compound 3 showed the strongest activity indicate that α configuration of hydroxyl group increases the cytotoxic activity.

Two new dammarane-type triterpenoid fatty acid ester derivatives, 3β-oleate-20S-hydroxydammar-24-en (1) and 3β-oleate-20S,24S-epoxy-25-hydroxydammarane (2) with a known dammarane-type triterpenoid compound, such as 20S-hydroxydammar-24-en-3-on (3), were isolated from the stem bark of Aglaiaelliptica (C.DC.) Blume. The chemical structures were determined by spectroscopic methods, including FTIR, NMR (one and two-dimensional), and HRESITOF-MS analysis, as well as chemical derivatization and comparison with previous literature. Furthermore, the synthetic analog resulting from transesterification of 1 and 2 also obtained 3β,20S-dihydroxy-dammar-24-en (4) and 20S,24S-epoxy-3β,25-dihydroxydammarane (5), respectively. The cytotoxic effect of all isolated and synthetic analog compounds was evaluated using PrestoBlue reagent against MCF-7 breast cancer cell and B16-F10 melanoma cell lines. The 20S-hydroxydammar-24-en-3-on (3) showed the strongest activity against MCF-7 breast cancer and B16-F10 melanoma cell, indicating that the ketone group at C-3 in 3 plays an essential role in the cytotoxicity of dammarane-type triterpenoid. On the other hand, compounds 1 and 2 had very weak cytotoxic activity against the two cell lines, indicating the presence of fatty acid, significantly decreasing cytotoxic activity. This showed the significance of the discovery to investigate the essential structural feature in dammarane-type triterpenoid, specifically for the future development of anticancer drugs.

Sesquiterpenoid is a class of terpenoid compounds that have the most abundant diversity of structures and biological activitiesthat can be found in natural resources. Tropical plants are main source of sesquiterpenoid compounds such as Aglaiagenus belong to Meliaceae family. A. harmsianais a species from Aglaiathat only has few previous researchs. Therefore, the purpose of this study was to isolate and determine the structure of sesquiterpenoid compounds from stem barkA. harmsianaalong withtheir cytotoxic activity against MCF-7 breast cancer cells. The isolation process begins by extracting powder from A. harmsianastembark using n-hexane, ethyl acetate and methanol. All extracts were evaluated for their cytotoxic activity against MCF-7 breast cancer cells, and n-hexane extractsshowed significant cytotoxic activitywith IC50values of 117.86 µg/mL. Therefore, n-hexane extracts were further separated and purified by various chromatographic techniquesto obtain compounds 1and 2. Compounds 1and 2were elucidated their chemical structures by spectroscopic methods includingIR, NMR, and MS as well as bycomparison of data with literatures and identified ascaryophyllene-typesesquiterpenoids, β-caryophylleneoxide (1) and senecrassidiol (2). Compounds 1and 2were submitted for cytotoxic eveluation on MCF-7 breast cancer cells and as a result, β-caryophyllene oxide (1) showed the stronger activity compared to senecrassidiol (2). These finding indicatedthat the cytotoxic activity of caryophyllene-typesesquiterpenoid areinfluenced by the presence of double bonds and configuration of methyl groups.

[Leu]6-aureobasidin K 1 is an analog of AbK, in which aIle residue at the sixth position of AbK is replaced by Leu. [Leu]6-AbK 1 was successfully synthesized using a combination of solid- and solution-phase that has a difference with the previous method applied for the synthesis of other aureobasidin analogues, [2S,3S-Hmp]-AbL 2. The linear precursor was prepared by using solid-phase method with Fmoc strategy, in which an ester bond was constructed on the resin. The cyclic product was obtained from a solution-phase reaction of the linear precursor using HATU reagent. The crude of the cyclic peptide was purified using a column chromatography technique to obtain [Leu]6-AbK 1 with a percent yield of 5.31% that is higher compared to previous similar method for synthesis of [2S,3S-Hmp]-AbL 2. The purity level of cyclic product was analyzed using analytical RP-HPLC (tR = 6.49 min) and analysis of structure using 1H-NMR.

Peptida antioksidan merupakan kelompok peptida yang berperan penting karena dapat menetralkan radikal bebas, sehingga dapat mencegah dan mengobati penyakit kronis. Salah satu senyawa peptida antioksidan alami yang telah ditemukan peneliti sebelumnya adalah senyawa tetrapeptida PAGY (Pro-Ala-Gly-Tyr) yang diisolasi dari gelatin kulit ikan amur sturgeon (Acipenser schrenckii) dan dilaporkan memiliki aktivitas antioksidannya dengan IC50 5.38 mg/mL dalam uji DPPH dan 0,008 mg/mL dalam uji ABTS berturut-turut. Kelompok kami telah berhasil mensintesis PAGY bersama dengan analognya yakni PSGY, PFFY, PAFY, dan PAIY dengan menggunakan metode sintesis peptida fase padat (SPPS). Pengujian aktivitas antioksidan pada senyawa hasil sintesis menunjukkan bahwa PSGY memiliki aktivitas antioksidan lebih baik dari PAGY. Pencarian analog tetrapeptida antioksidan yang lebih baik hingga saat ini masih terus dilakukan. Pada penelitian ini telah berhasil disintesis analog tetrapeptida lainnya PADY (Pro-Ala-Asp-Tyr) dengan metode sintesis peptida fase padat menggunakan strategi Fmoc/t-Bu pada resin 2-klorotritilklorida dilanjutkan dengan pengujian aktivitas antioksidannya. HATU/HOAT digunakan sebagai reagen pengkopling dalam sintesis PADY. Pemurnian krud PADY dilakukan menggunakan RP-HPLC preparatif sehingga diperoleh PADY murni seberat 14.7 mg (12.6%). Penentuan struktur peptida hasil sintesis dianalisis dengan menggunakan spektroskopi 1H-NMR dan TOF-MS. Pada pengujian aktivitas antioksidan dengan metode DPPH, PADY hasil sintesis memberikan nilai IC50 sebesar 1.850 mg/mL, yang mengindikasikan bahwa PADY menunjukkan aktivitas antioksidan yang lebih rendah daripada PAGY hasil sintesis peneliti sebelumnya. Kata kunci: Antioksidan, tetrapeptida, sintesis peptida fase padat. Antioxidant peptide is a class of peptides that play an important in neutralizing free radicals, therefore this compound can be used to prevent and treat chronic diseases. One of the natural antioxidant peptides reported by previous researcher is PAGY (Pro-Ala-Gly-Tyr), which is isolated from amur sturgeon fish (Acipenser schrenckii) gelatin that showed antioxidant activity with IC50 5.38 and 0.008 mg/mL using DPPH and ABTS assay, respectively. Our group has successfully synthesized PAGY, along with its analogues of PSGY, PFFY, PAFY, and PAIY using solid phase peptide synthesis method (SPPS). Antioxidant assay on synthesised compounds showed that PSGY has better antioxidant activity than PAGY. The search on the analogues of the antioxidant tetrapeptide was continued. From this study, a tetrapeptide analogue PADY (Pro-Ala-Asp-Tyr) has been successfully synthesised by solid phase peptide synthesis method with Fmoc/t-Bu strategy on 2-chlorotrityl chloride resin and tested for its antioxidant activity. HATU and HOAt reagents were used as the coupling reagent for the synthesis of PADY. The resulting PADY peptide solid was then purified using preparative RP-HPLC yielding PADY of 14.7 mg (12.6%). Characterisation of the synthesized compound was analysed by 1H-NMR and TOF-MS. On the antioxidant assay using DPPH method, PADY showed IC50 value of 1.850 mg/mLindicating a lower activity than the synthetic PAGY. Keywords: Antioxidant, tetrapeptide, solid phase peptide synthesis (SPPS).

Antimicrobial peptides (AMPs) are interesting compounds owing to their ability to kill several pathogens. In order to identify new AMPs, c-PLAI analogues were synthesized and evaluated together with their linear precursors for their antimicrobial properties against two Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus), two Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae), and two fungal strains (Candida albicans and Trichophyton mentagrophytes). The new c-PLAI analogues were prepared through a combination of solid- and solution-phase syntheses, as previously employed for the synthesis of c-PLAI. The antimicrobial activity tests showed that the synthetic parent peptide c-PLAI was inactive or weakly active towards the bioindicators employed in the assay. The tests also indicated that cyclic c-PLAI analogues possessed enhanced antimicrobial properties against most of the bacteria and fungi tested. Furthermore, this study revealed that analogues containing cationic lysine residues displayed the highest activity towards most bioindicators. A combination of lysine and aromatic residues yielded analogues with broad-spectrum antimicrobial properties.

Two dammarane-type triterpenoids, 20S,24S-epoxy-3α,25-dihydroxydammarane (1) and 3α-acetyl-20S,24S-epoxy-3α,25-dihydroxydammarane (2), have been isolated from the stembark of Aglaia argentea. The chemical structure of compounds (1 and 2) were identified by spectroscopic evidences including UV, IR, 1D-NMR, 2D-NMR and MS as well as by comparing with previously reported spectral data. Those compounds were isolated from this plant for first time. Compounds (1 and 2) showed cytotoxic activity against P-388 murine leukemia cells with IC50 values of 23.96 and 8.14 mM, respectively. DOI:http://dx.doi.org/10.15408/jkv.v4i1.7065

Two sesquiterpenoid compounds, 4(15)-eudesmen-1b,6a-diol (1) and spathulenol (2) have been isolated from the stembark of Aglaia minahassae belong to Meliaceae family. The chemical structures of 1 and 2 were identified on the basis of spectroscopic evidence including UV, IR, NMR 1D, NMR 2D as well as mass spectra and by comparison with those previously reported spectra data. This compounds were isolated from this plant for the first time.

Four dammarane-type triterpenoid compounds, dammar-24-en-3a-ol (1), 3-epi-cabraleahydroxy lactone (2), (E)-25-hydroperoxydammar-23-en-3b,20-diol (3), and dammar-24-en-3β,20-diol (4), were isolated from the methanolic extract of the stembark of Aglaia argentea. Compounds 1-4 were isolated for first time from this plant. The structure of isolated compounds were elucidated by spectroscopic methods including one and two-dimensional NMR as well as mass spectrometric analysis. Compounds, 1-4, along with a known synthetic analog, 20-hydroxy-dammar-24-en-3-on (5), were evaluated their cytotoxic activity against P-388 murine leukemia cells in vitro. The IC50 values of compounds, 1-5 were 9.09 ± 0.10, 68.53 ± 0.08, 5.89 ± 0.08, 22.40 ± 0.11, and 11.53 ± 0.08 µg/mL, respectively. Among the dammarane-type triterpenoids, compounds 1, 3, 4 and 5 having opened side chain showed the stronger activity, wheres compound 2 with cyclic side chain showed weak or no activity. In addition, compound 3 showed strongest activity, indicate that hydroperoxy group at side chain increase cytotoxic activity.

Two mixtures of flavanoid compounds (1 and 2), a mixture of catechin (1a) and epicatechin (1b), and a mixture of gallocatechin (2a) and epigallocatechin (2b), were isolated from the active fraction of the stem bark of Aglaia elliptica methanol extract. The chemical structure of the compounds was identified with spectroscopic data, including UV, IR, NMR (1H, 13C, DEPT 135°, HMQC, HMBC, 1H-1H COSY), and MS, and additionally compared with previously reported spectral data. All compounds were evaluated for their cytotoxic effects against P-388 murine leukemia cells. Compound 2 showed cytotoxicity against the P-388 murine leukemia cell, with an IC50 value of 7.79 µg/mL, but compound 1 was found not to be active (more than 100 µg/mL).

The Aglaia genus belong to Meliceae family is unique plant species because the presence of rocaglate and rocaglamide which is so far isolated only from Aglaia genus, indicate that type of this compound as a chemical marker for the genus of Aglaia. This type of compound known to have strong activity, such as insecticide and cytotoxic. This study describe the isolation, structure elucidation, and cytotoxic activity of an isolated rocaglate compound. Dried stembark of A. argentea extracted with methanol and partition between n-hexane, ethyl acetate, and n-butanol, respectively The extracts were tested against P-388 murine leukemia cells and the ethyl acetat showed strongest activity with IC50 value of 15.5 mg/mL. The ethyl acetate then was separated and purified with chromatography technique to obtain isolated compound 1. The chemical structure of isolated compounds were elucidated by spectroscopic methods including one and two-dimensional NMR as well as high-resolution mass spectrometric analysis and identified as a methyl rocaglate. Compound 1 showed strong cytotoxic activity with an IC50 value of < 0.1 μg/mL.

Three cytotoxic steroids, stigmasterol (1), stigmast-5-en-3b-ol (2) and b-sitosterol-3-O-acetate (3) were isolated from the stem bark of Chisocheton cumingianus. The chemical structures of those compounds were identified based on spectroscopic data and by comparison with those data previously reported. All of the compounds isolated were evaluated for their cytotoxic effects against P-388 murine leukemia cells in vitro. Compounds 1-3 showed cytotoxicity activity against P-388 murine leukemia cells with IC50values of 12.4, 60.8, and ˃ 100 mg/mL, respectively.

Tetrapeptide, OH-Pro-Ala-Gly-Tyr-NH2, was successfully synthesised on 2-chlorotrityl chloride resin by taking advantage of PyBOP (benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate) as coupling reagent. The selection of the peptide as the target of synthesis was due to its interesting bioactivity as antioxidant. The synthesis was undertaken with Fmoc strategy, where Fmoc-proline was added onto the resin at the first place. It is known from the literature that proline can resist from rasemisation when it was attached on the resin at the first time. Fmoc deprotection step was carried out by employing 20% piperidine in DMF and the reaction mixture was shaken for 30 minutes. Once the proline attached, the next step was to attach amino acids, alanine (Ala), glycine (Gly) and tyrosine(Tyr), subsequently onto the resin until tetrapeptidyl resin was constructed on the resin. Hydroxyl group of Tyr was protected with t-butyl, which is TFA-labiled. Coupling reaction was undertaken by mixing the amino acid and PyBOP in a mixture of dichloromethane and DMF (1:1) and in the presence of basic DIPEA. Resin cleavage step was carried out by using 95% TFA in water, where t-butyl protecting group on the side chain of Tyr was cleaved at the same time. The analytical RP-HPLC of the final product showed a single peak at 21.9 minutes (20-90% of acetonitrile in water with 0.1% of TFA during 30 minutes), indicating that each coupling has given a good coupling performance and resulting in a pure product. The desired product showed the correct molecular weight with m/z 407.2 [M+H]+ and 429.2 [M+Na]. DOI: http://dx.doi.org/10.15408/jkv.v0i0.4055

Two flavanoid compounds, catechin (1) and epicatechin (2), have been isolated from the stembark of Chisocheton pentandrus. The chemical structure of compounds1and2were identified byspectroscopic data including, UV, IR, NMR (1H, 13C, DEPT 135°, HMQC, HMBC, 1H-1H COSY) and MS and by comparing with previously reported spectral data. Compounds 1 and 2, were isolated in this plant for first time and showed no cytotoxic activity against MCF-7 breast cancer cells.