Uji Daya Hambat Daun Sirsak (Annona muricata L) Terhadap Bakteri Escherichia coli

Summary

This experiment investigates the antibacterial properties of soursop leaf extract (*Annona muricata*) against *Escherichia coli*. The study involves the preparation of the extract using maceration with ethanol, followed by testing its effect on bacterial growth through disc diffusion on nutrient agar. Different concentrations of the extract (40%, 60%, 80%, and 100%) are compared with ciprofloxacin, a known antibiotic, as a positive control. The results are measured by the inhibition zones around the discs after 24 hours of incubation. This experiment highlights the potential use of soursop leaf extract in combating bacterial infections.

Takeaways

• 😀 The experiment tests the antibacterial activity of soursop (Annona muricata) leaf extract against *Escherichia coli*.
• 😀 The extraction method used is maceration, with the leaves soaked in ethanol (96%) for 3 days and agitated daily.
• 😀 The soursop leaves are first cleaned, dried for about 10 days, and then blended into a fine powder before extraction.
• 😀 After extraction, the soursop extract is concentrated using a rotary evaporator at temperatures below 40°C.
• 😀 Sterilization of laboratory equipment is carried out using an autoclave set at 121°C and a pressure of 15 psi for 1 hour.
• 😀 Nutrient agar is prepared by dissolving 5 grams of the medium in 250 ml of distilled water, then sterilized in an autoclave.
• 😀 The *E. coli* bacteria are cultured on nutrient agar, and a pure colony is used for the antibacterial test.
• 😀 The antibacterial activity is tested with four concentrations of soursop leaf extract: 40%, 60%, 80%, and 100%.
• 😀 A positive control (ciprofloxacin) and a negative control (distilled water) are also used to evaluate the effectiveness of the soursop extract.
• 😀 After applying the extracts to paper discs and placing them on inoculated nutrient agar, the dishes are incubated at 37°C for 24 hours to observe inhibition zones.

Q & A

What is the primary objective of the practical in this transcript?

The primary objective is to test the antibacterial activity of soursop leaf extract (Annona muricata L.) against *Escherichia coli*.

What part of the soursop plant is used in the experiment?

The experiment uses young, physiologically mature leaves of the soursop plant.

How are the soursop leaves prepared for the extraction process?

The soursop leaves are washed with clean water, cut into small pieces, and dried for approximately 10 days before being blended into a fine powder.

What method is used for extracting the active compounds from the soursop leaves?

The extraction is done using the maceration method, where the powdered leaves are soaked in ethanol for 3 days, with daily agitation.

What is the purpose of using a rotary evaporator during the extraction process?

The rotary evaporator is used to concentrate the extract by evaporating the ethanol at a temperature not exceeding 40°C, leaving behind a thick extract.

How are the tools and equipment sterilized for the experiment?

All tools are sterilized using an autoclave at a pressure of 15 psi and a temperature of 121°C for one hour, followed by 30 minutes of laminar airflow sterilization and alcohol spraying.

How is the nutrient agar prepared for culturing *Escherichia coli*?

Five grams of nutrient agar are dissolved in 250 ml of distilled water, heated until it dissolves, and then autoclaved at 121°C for one hour.

What is the process for preparing the bacterial suspension for testing?

A bacterial colony of *Escherichia coli* is inoculated into nutrient agar using a zigzag streaking method, incubated at 37°C for 24 hours, and then suspended in 0.9% NaCl solution for further testing.

What are the concentrations of soursop leaf extract tested in the experiment?

The concentrations tested are 40%, 60%, 80%, and 100% of soursop leaf extract.

How is the antibacterial activity of the soursop leaf extract assessed?

The antibacterial activity is assessed by placing filter paper discs soaked in the various concentrations of the extract on the bacterial inoculated agar plate, then measuring the inhibition zone after 24 hours of incubation at 37°C.