Abstract. Batubara R, Surjanto, Hanum TI, Handika A, Afandi O. 2020. Phytochemical screening and antioxidant activity of agarwood leaves (Aquilaria malaccensis) from two sites in North Sumatra, Indonesia. Biodiversitas 21: 1588-1596. Agarwood of gaharu (Aquilaria malaccensis Lamk) has an antioxidant activity which can reduce free radicals. This research was conducted to analyze the chemical compounds of agarwood, and the antioxidant activities from two different grown sites, Laru, and Hutanabolon Village. Ethanol extracts of the agarwood leaves (EEAL) were obtained through maceration method. The phytochemical screening included the examination of secondary plant metabolites, while antioxidant activity was determined by free radicals scavenging activity against 1,1- diphenyl-2-picrylhydrazyl (DPPH). An observable parameter was the percentage of free-radical-reduction with different concentrations (40, 60, 80 and 100 ppm) and inhibitory concentrations (IC50) value by using regression equation. The phytochemical screening result showed that simplicia and EEAL from Laru grown site contained secondary plant metabolites, such as steroid/triterpenoids, flavonoids, saponins, and tannins, while simplicia leaves of agarwood from Hutanabolon grown site contained alkaloids, steroid/triterpenoids, saponins, and tannins, However, EEAL from Hutanabolon was found to only contain alkaloids. The f antioxidant activity of EEAL from Laru 27.887 ± 0.560 ppm was not different from Hutanabolon 27.807 ± 4.630 ppm. The EEAL from both Laru and Hutanabolon had a very strong antioxidant activity.

Abstract. Rahmawaty, Samosir JB, Batubara R, Rauf A. 2019. Diversity and distribution of medicinal plants in the Universitas Sumatera Utara Arboretum of Deli Serdang, North Sumatra, Indonesia. Biodiversitas 20: 1457-1465. The plants found in Universitas Sumatera Utara (USU) Arboretum has the potential to be utilized by the local community to meet their food and medicinal needs. The objectives of this study were to calculate the species diversity, to find out the various parts of plants utilized for medicinal purposes and to map the distribution of medicinal plants in the arboretum. Survey and interview methods were used to collect data. The species diversity was determined using Shannon-Wiener index. Geographic Information System (GIS) was used to map the distribution of medicinal plants. The results showed that there were 17 species of medicinal herbs, 21 species of trees and 12 species of poles in the arboretum. The diversity was classified as moderate based on the calculated value. The most predominant part of plants utilized for medicinal purposes were leaves. The distribution of medicinal plants was mostly clustered and uneven. The condition indicates still there is scope for additional planting of medicinal species to increase the diversity of species, especially in the western and the northern part of the arboretum.

To address concerns over plastics in the global environment, this project produced three wood plastics composites (WPCs) which could divert plastics from the waste stream into new materials. The three materials made had a ratio of 85%:15%, 90%:10%, and 95%:5% low density polyethylene (LDPE) to wood powder and were produced using the dissolution method. Physical and mechanical properties of each WPC were evaluated according to Japanese Industrial Standard (JIS) A 5908:2003. Their degradation in nature was evaluated through a graveyard test and assay test conducted in Coptotermes curvignathus termites. Results showed that density, moisture content, thickness swelling and water absorption of the WPCs fulfilled the JIS standard. The mechanical properties of these composites also met the JIS standard, particularly their modulus of elasticity (MOE). Modulus of rupture (MOR) and internal bonding (IB) showed in lower values, depending on the proportion of wood filler they contained. Discoloration of the WPCs was observed after burial in the soil with spectra alteration of attenuated transmission reflectance (ATR) in the band of 500-1000 cm-1 which could be assigned to detach the interphase between wood and plastics. As termite bait, the WPCs decreased in weight, even though the mass loss was comparatively small. Micro Confocal Raman Imaging Spectrometer revealed that termite guts from insects feeding on WPCs contained small amounts of LDPE. This indicated termite can consume plastics in the form of WPCs. Thus WPCs made predominantly of plastics can be degraded in nature. While producing WPCs can assist in decreasing plastics litter in the environment, the eventual fate of the LDPE in termites is still unknown.

Gaharu (agarwood) grows naturally in Sumatera, especially in Middle Tapanuli regency. The development of knowledge and research about gaharu leaf has been used as raw material for brewed beverage or tea. The purposes of this research were to observe the leaf used as raw material of gaharu leaf tea that grows naturally in Middle Tapanuli by looking at the chemical compound contained in the leaf which function as antioxidant and to know the antioxidant activity and tannin content of the leaf. Gaharu leaf from 2 growing sites (Sigiringgiring village and S. Kalangan II village) was identified, then processed into leaf simplicia and extracted with 96% ethanol solvent. Phytochemical screening of alkaloid, glycosides, steroids/triterpenoids, flavonoids, tannins and saponins compounds were conducted. The antioxidant activity test was performed by DPPH method to obtain IC50 (Inhibitory Concentration) value. The results showed that the agarwood leaf from Sigiring-giring contained terpenoids and saponins and from S. Kalangan II contained of tannins and saponins. The results of antioxidant activity test showed that agarwood leaf extract has IC50 value in 56,985 dan 44,382 μg/ml which meant strong and very strong antioxidant activity category.

Abstract. Rahmawaty,  Frastika S, Marpaung RME,  Batubara R,  Rauf A. 2019. Short Communication: Use of Geographic Information System for mapping of Aquilaria malaccensis land suitability in North Sumatra, Indonesia. Biodiversitas 20: 2561-2568.  The Geographic Information System (GIS) can be applicated in the field of forestry and agriculture, such as for mapping as part of land evaluation. The land suitability of Aquilaria malaccensis in the agroforestry land of North Sumatra Province is important.  Commonly, A. malaccensis were planted by the community in Langkat and Deli Serdang District. This study aimed to map the land suitability for A. malaccensis in Telaga Village, Sei Bingai Sub District, Langkat District, Peria-ria Village and Sari Laba Jahe Village, Biru-biru Sub District, Deli Serdang District. A survey method was used to collect soil samples in the field. Land suitability classification (LSC) for A. malaccensis was evaluated based on the matching method.  The results showed that the actual land suitability classes for A. malaccensis in Telaga Village were moderately suitable (S2) and marginally suitable (S3). The actual land suitability classes for A. malaccensis in Peria-ria Village and Sari Laba Jahe Village were moderately suitable (S2), marginally suitable (S3) and not suitable (N). There were several limiting factors in land suitability evaluation in the area, namely: nutrient retention (nr), erosion hazard (eh), and root zone medium (rc).