Judul: Aktivitas antihipertensi aktinomiset endofit asal tanaman pegagan dan belimbing wuluh
Abstrak: Endophytic actinomycetes lives in the plant tissue without causing a negative impact. Several medicinal associates with endophytic microbe which may produce similar bioactive compounds to their host plant. Inhibition of Angiotensin Converting Enzyme (ACE) is one of the effective antihypertension mechanism. The potency of endophytic actinomycetes from the medicinal plant used as ACE inhibitor needs to be elucidated. The research aimed to isolate endophytic actinomycetes from rhizome, stem, leaf of pegagan (Centella asiatica) and also from fruit of belimbing wuluh (Averrhoa bilimbi), and assess their capability to produce bioactive compound which can function as ACE inhibitor. The endophytic actinomycetes were isolated from surface sterilized plant parts, grounded and plated in Humic-acid Vitamin-B agar (HV) medium. The purified isolates were grown on International Streptomyces Project No.2 (ISP2) medium, and the crude extract which consisted of extracellular bioactive compound, was used for in vitro assay of ACE inhibitor activity. Twelve isolates of endophytic actinomycetes were successfully isolated from pegagan leaves (three isolates) and belimbing wuluh fruits (nine isolates). The data showed that nine isolates (AEP-1, AEP-2, AEP-3, AEB-1, AEB-3, AEB-5, AEB-6, AEB-7, and AEB-8), had various ACE inhibitor activities, and belonged to Streptomyces spp.. Three other isolates (AEB-2, AEB-4, and AEB-9) belonged to non-Streptomyces, and also showed various ACE inhibitor activities,. Meanwhile, free endophytic microbes of tissue culture seedling of pegagan did not show any ACE inhibitor activity. The AEP-1 isolated from pegagan had the highest percentage (279.2%) followed by AEB-5 isolated from belimbing wuluh (222,92%) of ACE inhibitor activity, exceeding the ACE inhibition activity of captopril (0.01 mg/mL) which was 61.5% and captopril (0.02 mg/mL) was 66.7%. The data indicate that endophytic actinomycetes isolated from leaf of pegagan and fruit of belimbing wuluh capable of producing ACE inhibitory compound.
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Judul: Kapang Endofit dari Tumbuhan Pesisir Sarang Semut (Hydnophytum formicarum) dan Potensinya sebagai Antihiperglikemik
Abstrak: Epiphytic plant sarang semut Hydnophytum formicarum is one of the coastal plants that used as traditional medicine. Microbial endophytic can produce secondary metabolite compounds similar to compounds produced by plants of its host. The purpose of this research was to determine the activity of the endophytic fungi extracts to inhibit α-glucosidase. This research included isolation, cultivation, extraction, characterization, and assay the antihyperglycemic activity. The results showed 7 types of endophytic isolates included 1A, 1B, 2A, 2B, 3, 6A and 6B with a different characterization. Endophytic fungus 3 and 6B were the selected isolate based on antagonism test. A fungal growth patterns showed that the stationary phase of the fungus was on the 21th day until 24th day. Phytochemical test on extracts of mycelium and culture media showed that the extracts containing flavonoids and phenols hydroquinone. The screening results showed that the fungal broth extract with concentration of 20000 ppm had α-glucosidase inhibitor activity 72.63%.
Keyword: α-glucosidase enzyme activity, sarang semut, endophytic fungi, antihyperglycemic

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular