This study investigated the antibacterial activity of extracts from four types of marine algae found along the coast of Benghazi, Libya. The algae tested were Cystoseira compressa, Enteromorpha intestinalis, Ulva lactuca, and Corallina. Methanolic and aqueous extracts were prepared from the algae and tested against three bacterial strains - Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. The results showed that methanolic extracts had higher antibacterial activity than aqueous extracts. Specifically, the methanolic extract of Ulva lactuca showed the strongest inhibitory effects against the tested bacteria, particularly P. aeruginosa. The study concludes that macroalgae from the Libyan

1. Libyan International Medical University
College of Pharmacy
Project of Graduation
Antibacterial Activity of Libyan
Macroalgae
By
Nada Hussein Zubi
Supervision
Dr : Salmin Alshalmani

2. Aim of the study
 To investigate the type and
Pharmacological activities of
seaweeds originated from cost
of Benghazi .
 To assess the antibacterial effect of aqueous and alcoholic
crude extracts of 4 marine algae from the eastern coast of
Libya, against pathogenic bacteria (1 Gram-positive, 2 Gramnegative).
1. Cystoseira compressa
2. Enteromorpha intestinal
3. Ulva Lactuca
4. Corallina

3. Techniques was used
 Extraction of active constituents.
 Microbiological tests

4. Terminology
Algae are a very large and diverse
group of simple, typically autotrophic
organisms, ranging from unicellular to
multicellular forms, such as the giant
kelp, that may grow up to 50 meters in
length. Algae were once considered to
be plants but are now classified
separately because they lack true
roots, stems, leaves.
The algae are one of the most
vast and diverse groups of
ancient photoautotrophic proand eukaryotic organisms
(about 30 000 known species).
They are mobile and immobile,
attached and free-living.

5. • They are thought to represent the earliest form of life on Earth,
forming at a time when the Earth's atmosphere was devoid of
oxygen.
• This has lead to conclude that algae are responsible for the early
accumulation of oxygen in the atmosphere, paving the way for other
plants and eventually animals to evolve.

6.  Algae are Highly Adaptable, come in all sizes For example,
phytoplankton, which lives in lakes and oceans, can
accumulate in the thousands just on a small pinhead.
Algae are found in the sea,
rivers, lakes soils, walls, in
plants and animals just about
anywhere there is light to
photosynthesize .

7. Types of Algae
In 1997 some scientists introduced a classification system that
breaks all algae down in 11 different phyta classifications,
• The most common are
• green algae, red algae, brown algae, golden algae and
cyanobacteria (blue green algae).
•
• Seaweed draws an extraordinary
wealth of mineral elements from the sea
that can account for up to 36%
of its dry mass.

8. Algae in Benghazi coast
• Benghazi coasts extend more than 18 km. at Mediterranean
Sea and very rich of marine algae but there is no recent algal
list related to that point. The present work was mainly intended
to collect and study the marine green algal population of
Benghazi coasts to enable other researches to evaluate their
chemical composition, antimicrobial activities and economic
importance.

9. Benefits of seaweed
Algae as food:
Algae are used
as source of food since 6000 year
ago by human beings. They are rich
in
carbohydrates,
inorganic
substances and vitamins.
Algae in industry: Diatoms (algae)
are extensively used in sugar
refineries and soap manufacture. It is
also helpful in cement industry, in the
manufacture of dynamite.

10. Benefits of seaweed:• As fuel: Algae are the fastest-growing plants in the world.
Different species of algae may be better suited for different
types of fuel. Algae can be grown almost anywhere, even on
sewage or salt water, and does not require fertile land or food
crops, and processing requires less energy than the algae
provides.

11. Pharmacological activities of seaweeds
• As Antidiabetic : Ulva rigida,
one of the green algae showed
antidiabetic and antihyperlipidemic
effects and improves oxidative stress
in diabetic rats.
• As antihypertensive :
• Six polysaccharides derived from
seaweed species were investigated,
and appreciable suppression of
hypertension and
hypercholesterolemia .
• They also markedly enhanced the
serum level of HDL

12. Anticancer and cytotoxic activities
• The new classes of anticancer drugs that have been isolated
from marine organisms have been shown to possess cytotoxic
activity against multiple tumor types.

13. Anti Microbial activities
• The green, brown and red algae
have been extensively screened
for:
antibacterial
antifungal
Antiprotozoal activities

14. ExpErimEntal
SEction

15. Material and method
 Collection of Algal material
Macroalgae were collected by hand picking form Benghazi coast (Alsabri) in
15 April 2013, the algae were cleaned and washed thoroughly in sterile sea
water, then rinsed in distilled water to remove salt.
 The taxonomic of samples was done by experts in these fields.
 All species tested are deposited in herbarium sheet.
 then dried for 48 hr in natural light in 25ºC, the dry seaweeds were crushed
in an electrical mill until a fine powder was obtained, and stored in bottles at
room temp .


16. Herbarium sheet of
(Cystoseira compressa , Ulva lactuca ,
Enteromorpha intestinal)

17. Microscopically examination
for the powder
• 1- Corallina

18. 2- Cystoseira

19. 3- Enteromorpha
4 . Ulva Lactuca

20. Extraction:
1. The powder (5 g) of dried algae
extracted in shaker apparatus
using 100ml of solvent for 24h at
25ºC.
2. The extraction done by several
solvent (water - ethanol( 99%) –
methanol (99%) – methylated
spirit (95%).
3. then the extract filtrated to remove
the insoluble material.
4. Then concentrated by evaporated
the solvent to dryness and the
solid residue then dissolved in 2
ml by the same solvent and

21. •
Antibacterial activity test:
The tested microorganisms selected were spoiled microorganisms or
common human pathogen, and were comprised gram- positive bacteria
staphylococcus aureus SH100, of the two gram- negative bacteria
pseudomonas aeruginosa ATCC 17933 and Escherichia coli ATCC 25922.
The organisms were obtained from the department of microbiology,
Benghazi medical center ,all cultures were kept on nutrient agar and stored
at 4ºC.

22. Antibacterial Assay:
. The test was performed by the Agar Diffusion Method
by a smear of microorganism applied to( Mueller-Hinton) plates using a cotton
.swap
the crud extracts were placed in 6 mm diameter wells made on the plates with
sterilized borer , the extract algae compound (100µl) was introduced into
.the well with electronic pipit
. solvent was also used as negative control
the plates were incubated at 37ºC, for 24hr

23. Antibacterial Assay:
the diameter of the inhibition halo is considered
to be indicative of the bioactivity of the
seaweeds extract .and was measured
( including the well diameter) with caliper
standardized values for diameters of inhibition
halo , expressed in mm.
diameter less than 7mm was interpreted as
inactive (-) .
diameter less than 9mm was interpreted as trace
active (+) .
diameter between 10 and 14 was interpreted as
moderately active (++) .
diameter more than 14 was interpreted as highly
active (+++).

24. Results and Discussion
Antimicrobial activity of liquid algae extract according to
solvent
•
•
•
Methanolic extract had the highest antimicrobial activity and the broadest
spectrum.
Water extract had the lowest activity with low bioactivity and narrow
spectrum of action
Methanol, methylated spirit, ethanol and water extract showing the
antimicrobial activity respectively.

25. • The results showed the effect of the
methylated spirit extract of Ulva lactuca.
significantly inhibited the growth of
pseudomonas aeruginosa. And this is
clear since the discoloration of the plate.

26. Antimicrobial activity of
methanolic extract of the 4 algae
1. The results indicated that Green
alga ulva lactuca is the most
active algae as
antimicrobial activity with highest
and the broad spectrum activity .
2. S. aureus was more sensitive
than all the stocks, with the
largest inhibition diameter.
3 . E.coli was more resistance
against all the solvents .

27. Effects of highly concentration of
methanolic extract of 4 algae
• when we study the highly concentration of methanolic
extract (10% , 15% , 20%, 25%) of 4 algae with the same
bacteria, significant result obtained from S. aureus, at 10%
conc there is no growth of S. aureus in the all plats ,the
algae kills all bacteria.

28. • With Sp.sp was obtained discoloration
for most bacteria in the plate

29. • no activity on E.coli even in the high
concentration.

30. Effect of algae extract after one year of storage
to the dried powder
• in April 2012 sergassium algae was collected and stored
in bottle in room temperature for one year , in April 2013
was extracted and
• there are no deference in the antibacterial activity
between the stored algal powder collected in 2012
• the active constituent are still stable.

31. Conclusion:
1. algae are used by human beings for food, from ancient times.
researches are being done in phycology (study of algae) to find out the
food value of algae.
2. their importance in industries and importance in agriculture.
3. Macroalgae from Libyan coast are potential bioactive compounds and
should investigated for natural antibiotics this study has shown that the
production of antibacterial substances is regular occurrence among
those found on the coast of Libya especially Green algae,.

32. RECOMENDATION
1 . Continuous researches on the other
possible activities on these 4 algae.
2. Consider the economic importance of
these type of studies, since the long
Libyan coast and high availability of
different types and species.
3. Continuous education and awareness
about the Marine products and their use
daily life as food, cosmetics, in agriculture
and more importantly as a fuel.
4. More study on methods of isolation and
separation of their active constituents .

33. THANK YOU